Disrespect to artists is, unfortunately, not a problem just on this site only. Take a look at the horror stories at
http://clientsfromhell.net/ for many examples.
I am ashamed to say that once I may have been one of them. I've said and done a couple of things to certain artists that, in retrospect, I'm not proud of. But after learning about the issues from some artist friends of mine I'm striving to be a better person. And it's all a long time ago now anyway (most of it was way before the existence of Eka's).
Speaking from my own POV back then, I think the real issue is that most people don't realize just how difficult and time-consuming creating good art is. It's often like "Hey, you do this for fun, right?", or "What are you complaining about, it's just a few doodles." Add to that the anonymity of the 'net which makes certain people say and do things they wouldn't dare to say face to face, and of course frequent and wide-spread misconceptions about copyright rules, and I think you have the root of the problem.
The only thing we can do is to let our artists know we appreciate them, and let the jerks know that their behavior is inexcusable and will not be tolerated.