I've never minded cartoons, but truth be told, the amount actual worthwhile ones coming out these days are few and far between. Most seem like they come out of the fevered dreams of a meth addict and their attempts at humor are painful at best, Go! is just another one of the bad ones.
I don't like Go! not because it's a cartoon, but because I think it fails on EVERY way it possibly could for reasons I've already stated. I don't mind that its a cartoon, I don't mind even that it's not a continuation of the 2003 series or even remotely like it, what I do mind is the blatant lies in it's marketing, inconsistent generic characterization, absolutely terrible attempts at humor, and often sickening actions of the characters that make any dark joke the Looney Tunes ever did seem bright as sunshine and rainbows. Again, the existence of the 2003 just makes it seem even worse because it serves as an example that they can do better than this, even on just the humor itself.
And no, I don't think Go! is harmless, if nothing else it's apparent success is setting a bad precedent for future cartoons ESPECIALLY any future superhero ones. If it's successful enough some executive somewhere is going to start taking cues from it, and that's a bad thing. Also yes, it did outright replace Young Justice and Green Lantern: The Animated Series, two much better shows, so people cannot be faulted for thinking that Go! had something to do with that.