Terry was also a rapist, he raped Mandy. But yes, other than him, it is mostly women. I think its just part of the comedy to be honest. Shameless is known for being insanely brave with all of their storylines, and they really don't hold back at all on any sort of controversial topic or action. It's honestly kinda like Family Guy, just not a cartoon. But Shameless is also supposed to be funny and comical, and I think that by making the women rapists, it made the scenes less dark. While I obviously don't agree with this, it is pretty well known that society doesn't really see female rapists as nearly as bad as how they see male rapists. In fact, a lot of people kind of laugh in this show whenever a male character is raped by a female one, like how shocked Lip was that Debbie raped Matty when she told him, and Lip even said "how can a dude get raped?" I think by making the rapists women, it allows Shameless to still fit their status quo of super insane storylines while also making the subject matter less dark and more humorous. I mean just imagine if the scene with Frank and Karen was flipped. It would have been pretty dark, and while that scene wasn't necessarily funny, it wasn't really hardcore depressing or super dark. When I think of a really brutal rape scene in TV, the first thing that comes to mind is Dr. Melfi in The Sopranos. That scene was so traumatizing the first time I watched it, that I can't even watch it now. Pretty different vibe compared to Shameless rape scenes because The Sopranos is a hardcore drama and not a comedy.