Out local troll(s) are basically like flat Earthers - they don't really care about the subject - in this case PMs or e-coin... they want to get a rise out of you and collect (you)s.
Every time you respond, they win.
Yeah, it takes discipline to refrain from responding. Filtering helps a lot.
>But others might listen to this guy
Not your problem.
>But he's wrong
Not your problem.
>He's messing up "our" threads
So are your futile responses, which give them an opportunity to reply and provoke and continue the cycle.
They're kids. Leave 'em be.

If you HAVE to respond, maybe include "IQ" in the text somewhere so a filter on that string will cut down on the noise.