Barriers to Quality at Wikipedia (and potentially other Wiki projects)
Honestly, I'm not sure.
How offensive is it? Obviously "shut up!" or "you're an ass" is not civil behavior. But is it offensive that the new user saw something they thought was untrue and said "stop pushing lies on Wikipedia. I'm removing your lies." Is it offensive if the new user said adamantly "listen, I'm an expert on this, and you need to step aside"?
And how original is the original research? If it's blatant, then that's a strike against you. But what if there are lots of people on the Wiki who think it's fair game? An admin comes down on you... and like many "true believers" do, they pour into the discussion and overwhelm the admin. They point out that the new user used a press release, or an advertisement, or a polished but self-published website. You point out that this is still original research, and they no it's not, and "ignore all rules" anyway.
... you're going to have a hard time dealing with anything but the most obvious vandalism. What makes "true believers" so disruptive is that they think it's enough that they wrote some grammatical sentences that are on topic, and there are plenty of people who will say that's fair game.