An addendum to this comment is the possibility of biased reporting, though.

If you're in an online PvP game and someone says (giving a gamut of possibles here) "go fuck yourself", "I'll fuck yer mum", "we fuckin raped you last round!", or "Suck my dick, loser" (all things I've heard in a single session in Overwatch, mind you), the respondants may give different opinions.

Anita Sharkhands would say that ALL of those statements are literally raping her, forming the words into corporeal form and just ramming it in in the most literal way possible please gib money nao. Karen McKaren might understand that "Fuck you" is not actually meaning the word fuck in a sexual sense, but would say the other three might be sexual harassment. Joe Gamer would accept it as just a part of dealing with online games, but might note "suck my dick" as a sexual harassment. Timmy Tryhard would just reply in kind, because it is the language of these games sometimes.

The study doesn't fully account for this difference in lenses. They try, but seriously, do you remember the number of times someone has said "fuck you" to you online?

It is entirely possible men also receive the bulk of sexual harassment by sheer count of incidents, but they discount it as being such because "suck a dick" said in passing isn't sexual harassment to them, they've been desensitized to hate of and derogation of male sexuality.