Why are Swifties so mean towards her exes?

I just came across a Tiktok video of Joe Alwyn being on the Drew Barrymore Show answering a question. I decided to take a look at the comments and they were all filled with Swifties saying hateful things. As far as I’m aware, Joe never did anything wrong did he? They’re acting as if they’re the ones who dated him and are still salty about the breakup. No other fans are like this at all. I know this has been a thing for years but it just seems crazy to allow your fans to harass your exes.