Because it's all regressive tropes rebranded as woke. Contrary to popular belief a lot of heterosexual ships are played for comedy and fun. Even Dysfunctional or "toxic" relationships like The Simpsons as a joke and to be ridiculed.
LGBTQ+ characters have a similar dysfunctional relationship but they constantly grandstand & soapbox about it to the detriment of the story. Instead of being kicked in the pants like everyone else, they're treated like poochies that everyone has to bend over backward to support. For example, Bart Simpson is a total ass but we laugh when karma comes to bite him in said ass. If Bart was LGBTQ+ he'd still be a complete asshole but the show would protect/always play him in the right without comeuppance. Plus a lot of characters lately are made LGBTQ+ to cover up shitty behavior. Being a dumbass, a genocidal tyrant, a pissed off manipulate pussy, etc is not excused just because you wear a rainbow flag or eat snatch.
Other characters in the show get completely derailed and degraded just for an LGBTQ+ ship, mostly by said LGBTQ+ character ruining their relationships or making everything about them. >TL;DR>They're often the most vapid and egocentric characters in the show never get the as whooping everyone else in show gets when they act like the LGBTQ+ character. Plus everyone acts like complete doormats for said LGBTQ+ regardless of pre-established story/character.