Male privilege theory is, ironically, the result of privilege.

most of what’s left open seems to be whether something is “unwelcome,” would you agree with that?

I think a lot of what's left open is outside of the realm of whether something is "unwelcome". For example, there are a lot of value judgements used in the wording of the items:

"Someone purposely touching you or brushing up against you in an unwelcome, sexual way"

Even if someone brushed up against a man in a sexual way, he might not interpret it as such due to cultural stereotypes and also less neuroticism, generally. And for the same reasons, if someone brushed up against a woman even without intent for it to be sexual she might interpret it as sexual contact.

"Someone repeatedly texting or calling you in a harassing way"

For an average man, it might indeed be unwanted, but he might not consider it harassing the same way or to the same extent your average woman would.

"Someone... leering/staring aggressively at you"

Again down to one's interpretations of the event and it's not hard to understand why women would perceive leering or staring as aggressive and why men wouldn't.

But I do think the "unwanted" label also proves problematic as I will expound on here:

Are you suggesting that men in retrospect tell themselves something was unwanted actually was or are you saying men want those interactions more. If it’s the former, that’s an interesting point I’d be curious to see any data on if it’s available;

I meant the former. The problem with male victims, especially male victims of female perpetrators, is there is a cultural sentiment that it's no big deal. It isn't hard to imagine that this might be internalized by many male victims and lead to displacement and denial, or sublimation of a non-socially acceptable emotion (trauma, anger, etc) into a socially acceptable one ("I got lucky!").

With regards to statistics and data on this:

http://www.austlii.edu.au/au/journals/CICrimJust/2014/14.pdf"Widom and Morris (1997) found men were much more reluctant to label child sexual experiences as ‘abuse’ than women (16% compared with 64%). Fondacaro, Holt and Powell’s (1999) study of male prison inmates also found that 41% of those who met the criteria for contact child sexual abuse did not consider their experiences as ‘abusive’ ... Other research that has linked men’s identification as a survivor of child sexual abuse to higher levels of psychological distress suggests that perceiving early sexual experiences as non-abusive may be a form of protective denial for men shielding them against painful memories (O’Leary and Gould 2010; Steever, Follette and Naugle 2001). This may mean that ‘nondisclosure is actually more adaptive for males than is disclosure’ (O’Leary and Barber 2008:135)."

So basically, males, for one reason or another, are really, really likely to re-contextualise the abuse they faced as "non-abusive". I can't help but wonder how this would affect the data about sexual abuse and sexual harassment.

if it’s the latter, I don’t see how that biased the data at all as something being unwanted is part of what makes it sexual harassment.

But the latter is an interesting and relevant point too. If our cultural norms were different, the results might possibly differ a bit due to men and women having different ideas of what they would want and not want. The way things currently are, men are told they should want and be thankful for any sexual contact from a woman and that it's good for them, so they may not see it as particularly "unwanted" even if they originally would've. If that makes sense.

I suppose the point I'm trying to make is that people's actions, reactions and perceptions of things differ based on what they're taught, and if sexual harassment is defined as any unwanted sexual advance, then women might be automatically more at risk of being sexually harassed because they are more likely to not want these interactions partially due to what they're taught. It may not be due to any differential treatment.