The simple fact that unlike almost every other Power Rangers series, the Time Force rangers don't kill their enemies. Threatening, deformed monsters or not, the mutants are still people, and they're still entitled to due process of law.
The Lightspeed and Time Force Rangers swapping jackets at the end of "Time For Lightspeed."
Carter: You got the jackets, now try the dance! [referring to the morphing gesture]
Time Force Rangers: Lightspeed! Rescue!
The first part of the finale when Nadira, with Trip's encouragement, helps deliver a baby causing her to question her father's hatred of humans and being the catalysis of her Heel–Face Turn.
Hell, the entire ending of the finale qualifies.
When the rangers encounter the Mutant Notacon, who's only crime was stealing vegetables because he couldn't get any food due to looking threatening, they decide to actually help him. Even if he's a mutant, the rangers don't judge him just for being one.
Trip defending Notacon when Eric wants to kill it and his words that Eric shouldn't kill him just for being a mutant, as is revealing he's an alien to Eric just to make the message stick.
One episode deals with Dash, a professional racer who also happens to be a mutant. He bears a grudge against Lucas because Lucas was the one who turned him in for reckless driving. Despite this, after nearly hitting some kids in the road during a street race, he realizes just how serious his crime was and agrees to come along willingly. If the end of the episode is any indication, that decision allowed him to serve his sentence, get out, and return to racing.
Wes's father coming around and admitting that he doesn't want Wes to follow in his footsteps and find his own path.
To emphasize this, in the first few episodes, money's all Mr. Collins cares about, to the point where Wes had to effectively con him into donating to charity and the Silver Guardians are only protection for those who pay, even at one point trying to buy the other Rangers into joining. By the finale, he is evacuating people into his limo and says the Silver Guardians are no longer a for-profit security force.
In "Nadira's Dream Date", otherwise a silly filler episode, we learn that, for all his racism, bloodthirst and general desire to see humanity crushed, Ransik is willing to put aside a bit of that hatred for Nadira's sake. If dating a Power Ranger is genuinely what his daughter wants, then that's what his daughter gets!
In the final battle, Ransik ignores the fact that Jen has knocked him flat and has a gun trained on him to go check on an injured Nadira. In the end, his love for her is what convinces him to stand down and surrender to the Rangers.
Not to mention that Nadira nearly got herself killed protecting a baby human, an infant of the very species he despises so. It's likely that seeing his daughter risk her life to protect the baby helped him rethink his choices.
It should be noted that Ransik had the Rangers on the ropes the entire final battle. He could have beaten all of them at their strongest easily, but his love for his daughter outweighed his hatred of humanity and caused him to surrender.
Eric finally stops hating Wes in the finale battles and goes so far to sacrifice himself to protect Wes and his father.
It's small, but Wes quietly checks up on Eric after he's been shot and jumped off a bridge. Nice to see that for all the distance Eric puts between them, Wes still cares.
The Time Force cast has proven to be one of the friendliest in the show's history. Everyone got along famously, with the actors even saying there'd been talk of having them continue for an additional season.