When someone repeats an argument that has been proven false /badly argued many times before, but keeps repeating it in hopes of drowning out opposition or derailing a thread. Yet not disruptive enough to get banned on forums, as it wraps itself in non-hostile, nicely written sentences.
How exactly do moderators deal with this kind of behaviour?
I think this is just a form of propaganda. If you really want a name then maybe Ad Nauseum.
Tricky to moderate. You need to identify, and have objective evidence of, a pattern of behaviour from a user. It needs to be enough that an independent ambivalent third party would agree that the intent is propaganda. I think this is kinda impossible honestly.
If its a small
fiefdomcommunity, just ban them.