@olea@mstdn.social @trixter This is a good lesson in being wary of responding to trolls. Trolls try to divert the conversation down a track where they have a (weak) excuse to say something abusive.
There were several red flags here. Brand new account. One of their first posts is complaining about the fandom. Hopping onto a random post to provoke a fight. It's a combination of these factors.
Avoid replying to them. If there is a potentially useful point to be addressed, do so in a different post.