>>98974313This is the main reason, as evident by Mike Lazzo's comment about why there aren't that many women working at Adult Swim.
Adult animation in the States generally just means a lot of gross-out humor and cursing, and it's proven at this point women don't really like shit, vomit, piss jokes. It's why Sarah Silverman even GAINED fame in the first place, as well as other women comedians like her. "Wooooweee! This woman is being gross, how very unusual!".
Since the bar is so low for adult animation (Or hell, TV animation in general), the writers who work on them are often pretty mediocre and not that versatile, so they would struggle to write for a woman protagonist anyway, which is why they avoid it. It's kind of why so many girl characters in cartoons are either love interests, kickass fighters or the creator's ideal fantasy "cool dream girl".
