The angry person you’re arguing with doesn’t want better understanding of the issues (do you?). They want the anger. It feels good to yell or to type out takedowns in ALL CAPS. Owning the idiots is a whole genre of online activity that looks like discussion but shouldn’t be mistaken for it. It’s performance–for the people on our side. Think about that the next time you narrate an argument you had to some of your friends.
Of course, we don’t have to engage people who disagree with us at all if we don’t want to. Maybe we shouldn’t. But if we must, then we should start with the anger. That’s more the substance of their issue (and ours) than the content of the argument.
YoRocko! 
Thank you. I will use this to help with some people close to me who send messages starting out with their anger about some perceived problem. I just type back “Good morning to you, too,” before I start trying to answer.