Whether such such trifling "transgressions" are bad or not really depends on the intent and the circumstances. If someone goes up to a female coworker every day and makes jokes about how women are stupid, then, yeah, that's pretty bad, and it needs to stop. The guy is being a jerk. It's not as bad as rape. It is bullying.
To me, it's not especially heinous because it's "sexual". It's on the level of going over to the system administrator's desk every day and making jokes about nerds playing sports poorly. It's harassment. It's bullying. There's something wrong with you if you're doing that to people, but no one is getting raped.
If it's people making jokes with each other because they're teasing each other because they're friends, then that's totally different and it's completely okay. But if someone doesn't like being teased, and makes that known, it will stop on its own in that case without outside intervention. But if it's really that horrible for you to be teased a little by someone with no ill intent toward you, you're extremely thin-skinned and there's something wrong with you (though not nearly as much as with the bullies in the previous paragraph).
So, basically, it all boils down to intent, and, for this stuff, in the case where something bad is going on, the "harassment" part is much more important than the "sexual" part. The only reason anyone cares about the sexual part at all is because lawyers and thin-skinned feminazis who want to be offended about something.
Now, for the more serious stuff: if people are getting raped in the workplace, then that's absurdly horrible, I can't imagine /HOW/ that's even happening because aren't there other people around?, and people need to go to jail. But I can't imagine people actually raping each other in the workplace often because in most workplaces I'm familiar with it would be pretty hard to have /consensual/ sex without getting caught and fired. But, I've never been on an archeological dig, so maybe I'm missing something.