Isle of Dogs: One of the dogs on Trash Island, Gondo, says that he and his pack have a choice: either eat a comatose dog to survive or starve to death. They end up eating said comatose dog, and even though Gondo says that they did what they had to in order to survive, he still feels ashamed of doing it.
Bad Cop has to justify doing this in The LEGO Movie, since it's his and Good Cop's neck on the line if he doesn't Kragle his own parents as punishment for failing to capture the Special. Both sides were clearly distressed to hear that they had to do this to their own parents; but Bad Cop did it because he knew the harsh consequences that would otherwise happen if they didn't obey. Unfortunately, this becomes the case when Good Cop can't bring himself to do it, winning out his other side and having his own face wiped clean off as a result.
In My Little Pony: The Movie (2017), this is Twilight's justification to the rest of the Mane 6 for attempting to steal the hippogriffs' Pearl of Transformation — every attempt at using the power of friendship outside of Equestria so far has only gotten the ponies in more trouble, so she decided to forgo it entirely. This backfires horribly.
The Prince of Egypt: Subverted. Seti expresses regret in regard to ordering his soldiers to slaughter the Hebrew newborns. However, his following remark makes his real feelings about the matter even clearer.
Seti: Sometimes for the greater good, sacrifices must be made... Oh, my son. They were only slaves.
In Wreck-It Ralph, Vanellope steals Ralph's medal to enter into the nightly race. In order to enter the race she needs a gold coin, but she can only get a gold coin if she's able to race. When Ralph confronts her, she's remorseless, pointing out that she had no other choice.
Later in the movie, after finding out that Vanellope is a glitch and her showing up in the race could result in it being shutdown (which would kill her), Ralph smashes up her car, saying he was Doing It For Your Own Good, but he clearly feels this way about it afterwards.
Live-Action
10 to Midnight: Kessler asserts this with regard to framing Stacy, never apologizing in the least as he thinks it was right to put him away no matter what.
Stella: What did you do to yourself? Eben: What I had to do.
Assassin's Creed (2016): Joseph Lynch's first scene is immediately after Mary's death and he is constantly repeating the Creed like a Survival Mantra, as if he's trying to reassure himself that he did the right thing.
This is Felicity Shagwell's excuse for sleeping with Fat Bastard in Austin Powers: The Spy Who Shagged Me. However, Austin's not so much bothered about the ethics as the physics.
In The Battle of Algiers, Mathieu delivers a speech on this theme to the French press, justifying his use of torture in combating the Algerian insurgency.
Mathieu: Should France remain in Algeria? If your answer is "yes", then you must accept all the consequences.
One team in Cannonball discovers their fan belt has broken and head to a shopping center to get a new one. However, they can't find an auto parts store and reason that the only way they can get a fan belt is to steal one from one of the cars in the parking lot. That's what they end up having to do, but they leave behind some money and a note explaining why they did it.
Carriers: In a world where there's an infectious virus that kills people, pretty much everyone is forced to kill people who are infected but not yet dead. On some occasions our 'heroes' kill some non-infected people when they refused to give up gas in their car. They needed this gas to survive.
In Dangerous Beauty, this is Veronica Franco's justification for why she became a courtesan: "I repent there was no other way open to me. I do not repent my life."
In The Dark Knight Rises, this is done by Jim Gordon when he is called out by John Blake over hiding the Two-Face murders by blaming it on Batman. An interesting take, however, as this is suggested by Batman himself, he is never seen as a villain or a Knight Templar, and since the audience has seen the exact decision process behind it, is does seem like the best idea at that point in time.
In Dracula Untold, this is Vlad III Dracula's reason for becoming a vampire, as well as his reasons for the impalings earlier in his life.
In Draft Day, the Browns general manager Sonny Junior fired his dad as the head coach, because his father was at risk of dying during his stressful job. Firing him would have resulted in some relaxed years. Too bad his dad died anyway.
In Dr. No, James Bond invokes the trope after he knifes a guard and Honey Ryder gives him the What the Hell, Hero? treatment. Some latter-day reviews of this film point out that there is actually little plot justification for Bond killing this particular man, other than continuing to establish the "licence to kill" aspect of 007 in a way Ian Fleming never did in his books. (According to Word of God, this is why Bond is shown murdering Professor Dent earlier in the film, again an event never depicted by Fleming.)
Early in Friend of the World, Gore plays a recording that explains some of the story we missed. He can be heard on the tape quoting this trope word for word before he turns it off.
Jumper: When the protagonist David reproaches his mother for abandoning him when he was a kid at the end of the film, she responds by saying this trope word-for-word.
In Lincoln, Thaddeus Stevens is eventually forced to compromise on his principles to claim that he only wants equality before the law, not total racial equality, in order to get the 13th Amendment passed. When brought to task for his statement, an unrepentant Stevens asserts that he'd do just about anything to end slavery.
In Guardians of the Galaxy Vol. 2, Ego says these exact words when explaining to Peter Quill why he left Meredith, Peter's mother, if Ego loved her so much:
Ego: I returned to Earth to see her three times. And I knew if I returned a fourth, I'd never leave. The Expansion, the reason for my very existence, would be over. So I did what I had to do. But... it broke my heart to put that tumor in her head.
In Avengers: Infinity War, Thanos uses this to justify sacrificing Gamora for the Soul Stone.
Peter Quill: Asshole! Tell me you didn't do it! Thanos: I... had... to...
Early on, a former colleague of Strange's who was dusted asks him if he really, absolutely had to give up the Time Stone to Thanos, considering all the pain and suffering it caused. Strange reiterates his justification of "It was the only way."
This appears to be a philosophy that every Strange across the multiverse ascribes to. Strange even quotes this verbatim at the beginning. However, he ultimately defies this by choosing to believe that America can control her powers on her own instead of absorbing them and killing her in the process.
Predators: Royce is willing to sacrifice his fellow humans and abandon the wounded in order to survive, and often invokes this trope when Isabelle calls him out for it.
A light-hearted version in Running Scared (1986). The two cop heroes are in a hostage situation with a gunman who doesn't have any pants (long story). He orders them to take off their pants and give them to him so (a) he'll have a pair and (b) it will be harder for them to follow him. They do so. Later in the station house they're asked how they could give up their pants, and one of them says "We did what we had to do."
Mal: I don't murder children. The Operative: I do... if I have to.
Played for Laughs in Serial Mom. The entire premise is that a suburban woman feels morally justified in offing people for bad manners, not recycling and fashion faux pas, like Patricia Hearst's white shoes after Labor Day. Though funny, John Waters has stated that he feels very strongly about all these grievances (especially the last).
In Tell No One, this is how Jacques justifies helping Margot fake her death and not telling Alexandre about it; he was trying to keep Margot away from Gilbert, since she had killed Gilbert's son.
In Trumbo, Edward G. Robinson says "I did what I had to do" while explaining to Trumbo why he named names to HUAC.
Featured prominently in the second of many speeches in V for Vendetta.
Played straight to the letter by Ozymandias of Watchmen, who not only goes to ridiculous lengths to dupe the world into think they're under attack (and killing millions in the process), he also kills his beloved Bubastis in a vain attempt to kill Dr. Manhattan.
In X-Men: The Last Stand, Professor X tells Wolverine he did what he had to do in suppressing Jean's powers and her violent Phoenix personality.
In The Wolverine, during a dream sequence, Wolverine tells Jean Grey that he had no choice but to kill her because of all the death and destruction she was causing.
In Zombi 3D when Dr. Holder and his assistant, Norma, confront General Morton as the infector's body is burned, Morton uses this as an excuse.
Dr. Holder: Who told you to burn the body of the man infected with Death One? General Morton: ...I had to close an episode.
