It’s called trolling or just being contrarian in it’s milder forms. Every single online discussion every where gets a few posters arguing the earth is flat or Trump won 2020. The farther people are from the person topic incident or celebrity the freer they can feel to say outrageous things because the person is just a fictional character to them. Other people like arguing for its own sake and will get twisted into tangles keeping an untenable position.
BTW in general people’s online behavior can be much worse than IRL behavior.