I don't like fighting with anyone, especially friends. If someone has an issue with me I want to know what the issue is and how to fix it. I let them be mad, because in all likelihood I deserve it, and then when some time passes I try to rebuild the bridge.
There has to come a point where both step back and see if the fight is actually solving anything. Is it now a barrage of attacks? Or are new points being brought up that are relevant to the fight? Once people begin to attack me personally, I'm done. There's no need to do that if they want to really resolve anything with me.
I don't know if I've ever had "fights" with friends online, but small arguments. We quickly agreed to drop the subject and do our own thing. I don't believe I've ever had an online friendship diminish due to arguments.
I had a pretty good friend, and we were tele-co-workers for some time. We even met up when I went back to the States in 2014.
He couldn't agree with my politics (not going into it, just knowing what side of the aisle I was on) and blocked me in 2016.
Such a strange world we live in today. You used to be able to talk politics (albeit sometimes heated) at the dinner table. Now, people will just completely cut you off.