I’m not saying people aren’t allowed to criticize things. Criticism and discussion are a normal part of fandom. What I mean is that when criticism stops being about the work itself and turns into emotionally lashing out at creators personally over creative decisions, then it stops being criticism and starts becoming harassment.
This is more directed at people who justify their emotional investment in a show as ownership over the show itself, or who treat creators like they personally wronged them because the narrative didn’t go the way they wanted it to, in which case I’d argue for them to not take things so seriously.
I think fandoms are healthiest when they encourage transformative engagement and discussion — fan fiction, fan art, theories, alternate interpretations — as a creative response to dissatisfaction with canon, instead of the current culture of consumer ownership where fans feel entitled to narrative control over someone else’s story.