UNMARKED SPOILERS BELOW
Barbarian and Sexual Harassment/Abuse
(quick note: this was written by a man who has never had to directly deal with anything I'm about to describe, so to any women or anyone who actually has experienced any of these treatments, or objects to the way something is described or phrased, feel free to correct or expand as you see fit.)
Thematically, Barbarian is largely about how men fail to understand the gravity of how dangerous the world can be for women, or the impacts of their own actions.
Looking at the men in the film first to see how this is explored, Frank is a fairly obvious starting point, as it's his kidnapping, abuse, and rape of various women and their children that led to the eventual birth of The Mother, the main antagonist of the film. Although it's hard to say what Frank's view of The Mother is, it's clear that she, easily the most monstrous and strongest character in the film, is afraid of him, since she doesn't dare even approach his room when AJ arrives there, which seemingly implies that their relationship was abusive at some point in the past. As, well, a serial kidnapper and rapist of several generations, Frank obviously feels no remorse for his actions; however, considering his obvious fear of the police, the fact that he attempts to remain polite and cordial to people in public, and is clearly affected by AJ calling him disgusting over his snuff films, it's clear that he can at least grasp that his abuse would reflect poorly on him, though it's doubtable that he understands, or perhaps cares, all the irreparable harm he has done to the various women in his basement, their (and his) children, and, indirectly, all the people The Mother may have dragged to the basement.
AJ is, in himself, a whole other can of worms. Obviously, the subplot about his sexual assault of a co-star is not only contrasted with Frank's own abuse, it's made worse/more unsettling since he refuses to ever truly take responsibility for it (until a brief moment in the climax... where he then basically immediately goes back on his word) to a degree where until the club scene where he essentially admits his crime to a friend, it's actually left somewhat ambiguous whether the rape actually occurred or not (since the audience is locked into a perspective where we are only allowed to see what AJ tells other people about the event). It takes not only being exposed to another, far worse rapist, as well as being manhandled (and essentially, in a certain way of looking at it, sexually abused himself) by the Mother, for him to actually get somewhat reflective of the damage his own actions have caused, which comes out in a double-meaning speech to Tess and Andre concerning his culpability in Tess's gunshot wound. However, even after all that, he is STILL willing to put Tess's bodily safety at risk when he stands to gain from it, an action which underestimates the Mother's empathy and gets him brutally (and honestly? Deservedly) killed.
Even the "nicer" men in the movie have a tendency to "mansplain" or downplay Tess's suggestions or assertions. The cops basically dismiss her out of hand when she calls for help, Andre shows a condescending sense of knowing more than Tess and AJ concerning the Mother... an egotistical stance that gets him killed. Even Keith, arguably the kindest and most pure man in the movie, initially questions Tess's hesitance to "put herself back out there" after a bad relationship, and her constant skepticism, in a manner that suggests that even if he "knows", he doesn't truly understand the gravity or power dynamics of intrapersonal relationships from a woman's perspective. (Ironically, his disregard for the skeptical behaviour he calls Tess out for is actually what gets him killed by the Mother, since he insisted on checking the basement despite how sketchy she explained it was). Furthermore his behaviour, seemingly unwittingly, comes off as unsettling, creepy and sinister to her, suggesting that he is at least unaware of how to conduct himself in a way which is considerate of her feelings and the way in which she (and, by extension, women in general) interact with men and the world.
Tess is the only one who survives the Mother by virtue of understanding what the Mother actually is and wants: she's essentially a scared little girl who wants to provide others the care she never received, in the only way she's ever been shown: by her own Mother. It's through empathy, and actually trying to understand what the Mother wants, that Tess is able to not only survive her time in the pit, but also escape, and to eventually distract the Mother long enough to regretfully put her out of her own misery.
