The brainwashing gets us all. It's sad when it gets us while we're trying to be supportive. The proper expression is "I was horrified and angered by it," not "I will respond to this by aggressive behavior not that much unlike what the other dude did". And proper response to someone noticing it is, probably, "oh... um, I didn't think about it like that, thanks, sorry", not "but I had good intentions!!!"
He showed a naked picture of himself to her in a situation where the default balance of power was firmly in his favor. An interviewer blotting himself (if only using a photograph) in front of a potential peer or subordinate is an act of sexual aggression if I ever saw one, and you are claiming some sort of moral equivalence with reacting aggressively to it? You cannot be serious.
I was horrified and angered by it, and I know very well that assholes who show their bare butt pictures in interviews are incorrigible bastards, and if I happen to meet one, I am afraid I won't be able to contain myself(not too sure I would want to), so it was for the best I wasn't around.
Yeah, sure, people like him that should be shunned, and preferably prosecuted. But, actually, one of the reasons they feel free to do things like that is the culture of domination that's not really hurt in any way by people making violent remarks about them.
Amusingly, your statement "the brainwashing gets us all" was most appropriately applied to your own presumption that he would fit some male role when being uncomfortable with proximity and anger.
Maybe his response would be to call the interviewer's boss and describe the actions. Maybe his response would be to write a blog post and do all the SEO in the world to make sure it shows up #1 every time someone Googles the company in question. You are assuming that the reaction he wants to contain is punching the interviewer in the face - when he never says anything to that effect at all. There are plenty of possible actions that are not violent and are not morally equivalent to the interviewer but are still plenty regrettable.