At this point it's just people being sick to death of the same trope being done over and over again. There is a real overrepresentation problem going on in the animated world right now so seeing yet another attractive female being made gay solely to appeal to a specific crowd is going to make people sick and tired of it, especially when it's obvious the creator just wanted to appear woke.
It's just a natural reaction to oversaturation, and that's also not going into for how some people actually need more then just a design to get off.
Some people need to know her mood, how she talks and reacts, for others that might be the entire appeal of her. They care less about her design and more about her personality.
And for some people having a massive lesbian shaped wrench thrown into the works makes them lose that attraction. Now the personality they loved is just, incompatible with them, making something as simple as self inserting pretty much impossible.
Really you should count yourself lucky your brain doesn't put a random ass limitation on itself. Shit like this really makes being a coomer a pain in the ass sense you need to get into a series first before you can even think about cooming to the girls in it.