I've been thinking about this more, and I suppose it just trivializes something that's already too trivialized. These jokes may not lead to people becoming rapists, but if sex is taken lightly enough, I suppose somebody trying to have sex with someone wouldn't really think about the possibility that anyone takes sex seriously. People not wanting to joke about it restores some of the sanctity; I suppose it would make people think twice before just getting laid for the fun of it, if they see people who take it more seriously.
I'm wondering if I shouldn't joke about drunkenness, now, for the same reason; it's something very trivialized that shouldn't be. Bringing a serious note into people laughing about how drunk they got might make people think a little more before getting hammered again. I don't think it'll do much, but I might as well do what I can.
Another thing that got me thinking about this in terms of trivializing things is my reasoning for all the jokes my friends made about each other's heritage in high school. I'm Polish, a friend of mine is Russian, another is black, another's a mutt, and another's Mexican. We'll joke with each other all the time, things like, "I guess the doorknob's too complicated for a Pollack!", and making these racist jokes at each other because it highlights the stupidity of racism!
Occasionally someone walking by would get really offended when we made jokes about my black friend, and they'd come over wide-eyed, saying, "You shouldn't say that!". Every time, my black friend would look them straight in the eyes, and say, "Begone, Cracker!". Or when my dad was asking a Mexican he works with why Mexicans always drive apehangers (those motorcycles with the handlebars above your head). Carlos responded, "We're used to having our hands up!" Joking about this trivializes something that is inherently stupid; I can't take legitimate racists seriously, because I connect their comments with all the stupid jokes we make, and they lose their power as a result.
But trivializing something that's not stupid, and something that we have control over (unlike death), that's where you can run into issues.
May God bless us all!