I'm not saying you did it, but the same thought stream applies whether its you or someone else.

If fan art is illegal, why do so many people offer commissions? What about entire artist alleys at comic and anime conventions that are mostly fan-art driven? Don't you think that's unnoticed by copyright holders? What about the artists in those alleys, who draw someone's favorite anime character or superhero on the spot for cash (and many of these people are reputable artists, too!) Does that mean that if I want Tarzan drawn that I should stick with crappy drawings or hide in the stairwell with cash to give to someone to draw because its "illegal" and Disney's going to put both of us in jail?

I'm not blind to the effects, I know of artists getting cease-and-desist letters. I've heard of many of them (the last notable one was the Batman comic artist who did a parody of the Saturday Evening Post). But there's a difference and a method to it, otherwise these activities and events wouldn't be so widespread. You're allowed to make fan art under stipulations. It also depends on the interpretation of the copyright holders. (i.e. Star Trek fan-film) Drawing fanart is one thing. Drawing someone's trademarked property then claiming it as your own is something completely different. There's a thing called derivative works that allows you do these sorts of things to an extent.

If you have a problem with it, that's certainly fine, I'm not here to change your opinion. But this is a very in-depth issue that doesn't deserve to just be slapped with "that's illegal".