Let me start by phrasing it in geek:
Sexual harassment != Telling a dirty joke
Sexual harassment != Complimenting a colleague
Sexual harassment != Flirting
Any of these things can = generally unprofessional behavior. But, to each workplace its own. And what's unprofessional behavior in one office, might well be the status quo in another.
Sexual harassment, on the other hand, is just one of the many established, crystal-clear, and obvious-to-everyone-involved-in-it-no-matter-how-much-they-pretend-its-not forms of bullying that take places every day (but less so, on a positive note, much less so) in America.
Sexual harassment is something you do *at* someone, not *with* someone. If the person on the other end is not enjoying it, is uncomfortable with it and, especially, if their discomfort is the reason you're doing it, that's sexual harassment. Is the reason you're hurling the comments and behavior around because you want to underscore which side of the power dynamic you stand on? That's sexual harassment.
To wit, during the halcyon days when I was a newbie cocktail waitress at the bar, I remember being on the wrong end of sexual comments and behavior that made me really uncomfortable a lot. And the reason the fellows in question enjoyed hurling the comments and behavior my way was because they thought it was hilarious that it made me uncomfortable. If it didn't bother me, they wouldn't do it. Thus, to the Herman Cain defenders of the world, it was my fault they did it because if it didn't bother me, they wouldn't do it. Which is kind of like saying it was my fault I got the broken rib because if I'd been wearing suitable body armor they wouldn't have felt like punching me. Does that seem hyperbolic? Is a little hyperbole really worse than entrenched, cultural victim-blaming (hint: it's not).
How about another example: if you're out with your buddies and you compliment the waitress on her nice ass, you're not doing it to pay her a compliment. You're doing it because it makes you feel like a bug guy in front of your friends at the expense of the waitress.
And, you know that's why you're doing it. You know what sexual harassment is. Stop acting so dumb. I know that decades of lazy sitcom stereotypes and beer commercials have tried topawn off the notion that men only act like assholes because they're too dimwitted to know how to behave like civilized people, but, come on, you're not. You know you're not. You know what sexual harassment is. Grow up.