If everyone used it, how would they pay for the websites you enjoy, such a Youtube, MMO-C, (Possibly) Facebook? That's right, they'd make you pay for them. Would you rather not look at adds and pay money, or just ignore the adds?
It's always great to have malware served by ads, ow wait that does not happen to me because i am an adbock user.
Don't get me wrong, i do think its wrong to use since websites lose income to it, but as long as its possible to get malware served that way (wich happens quite often) i do not see a reason not to use adblock.
If, for example, you're watching someone's stream and part of their income comes from running ads, I'm not sure how you can claim they're being greedy by asking you to disable it.
But most of the hate I see for it comes in response to the douchebags who brag about it instead of keeping their mouths shut. No one cares if you have it so long as you don't make a point to say you have it.