...to the integrity of the characters and insulting of the artists behind them.
Why, I can only imagine is because childhood sexuality is seen as an innately negative expression, for the person expressing it as well as everyone responding to it erotically. It is something that simply "should not be". Although, in actuality it's pretty normal.
It's the perceived sexualization of previously innocent portrayals that gets people's panties in a twist.
There's arguably a difference between producing one's own content and keeping it to oneself versus distributing and profiting off of content inspired by another's "chaste" content which the another doesn't want to share for that particular purpose. But the latter is maybe just what happens with a creative commons, the type of free-for-all multimedia artistic network that the internet enables us to have.
I fall on the "freedom's more important" and "this isn't really harming anyone" and "censorship is immoral" and moreover, "who gives a fuck, it's just cartoons" side of the fence. Also the "you people need to get over your sexual hangups" side of the fence "because sexual attraction is a genetically driven physiological response that almost every single one of us feels and has no control over - something that happens, not something we do".