I don’t care to dig it up because he’s a loser and it doesn’t matter, but the guy that wrote Dilbert had some essay where he explained that fighting with people, online or irl, gave him energy. He (cringily) compared it to a lion feeding. I take that at face value for people on the more sociopathic/psychopathic/narcissistic/antisocial side neurologically. They just enjoy it and it pumps them up. They’re demons.
For normal people, I think it only happens when something else sets them off by either being profoundly stupid (hence the term bait) or offending them personally. If it and any subsequent flaming cuts deep enough on something personally sensitive, they can go “on tilt” and behave more like an ASPD/NPD for a while, starting shit elsewhere. So there’s a domino effect where if you tolerate antisocial behavior, they will then put even normal posters on tilt, who then set more people off, and basically even one ASPD can set off a fractal domino effect that takes a while to burn out. That’s why you have to ban them, permanently if they’re ASPD or temporarily until they cool down if they’re just on tilt.
If you’re not ASPD, the only way to avoid it is either not going places that will have content that sets you off, or work through whatever made you so sensitized to that topic until it doesn’t bother you anymore. I only have one or two things that set me off anymore, but on the rare (once a year or less maybe?) occasion that nerve gets hit I invariably sperg out until I get banned.