And as far as i know most casinos doesn't geo restrict any website access and registrations, some gives a warning not to register, but most doesn't, yet this casino restrict its users from registering as per my experience.
This case doesn't differ from those casino users who deny their own country and doesn't know how to read ToS, then complain later on.
He's a troll, but his useless posts and allegations can make anyone pissed. There should be a way for projects to eliminate such users in the forum because even though no one might believe what they keep repeating, they are still annoying. We can ignore them to avoid seeing their posts, but new users visiting the thread would, which shouldn't happen. There should be a rule in the forum for banning users or imposing some restrictions when they make accusations without proof.
I'm highly annoyed, but I think there is no other choice than to ignore him because reporting his posts won't do much, as he will make more. Such people are the reason why having self-moderated threads is a relief sometimes. You can remove their posts to keep the thread flowing without disturbance or annoyance.