There are three types of chronic arguers mainly.
One will argue when they find the least little logical inconsistency, and they have to fight with you until you admit you're wrong. They're also the ones that get so internally worked up when someone disagrees, no matter how trivial, it's probably akin to physical discomfort. Like nails on a chalk board.
Then there are the ones that seek out conflict, and argue for the sake of it. They usually argue because they secretly enjoy watching you struggle to explain yourself, when you both know you're right anyway. These types, ironically, get offended to the point of becoming abusive if anyone does it to them. Before you know it, they're straight up insulting you. These are the worst if you ask me, because they're so hypocritical.
Third is all about ego. They get their identity wrapped up in being correct. You could be watching the sun set on the horizon, and they would insist that it's not west. They fight until they make themselves out to be idiots, but hey, at least their self esteem is afloat.
Stay away from them all, online or otherwise. Don't engage with emotionally-challenged weirdos like that. They're poison.