The last one linked above was racist
That wasn't racist. People having difficulties with different nationalities (regardless of race) has been going on since the beginning of political borders. It's the same thing as complaining about the Chinese, which is very much tolerated here, at least as far as I've seen.
Moderators are NOT protecting scammers
Not in this instance, but the forum as a whole
does protect them in so far as scammers don't get banned.
even if I would like to see some rules for scammers similar like for spammers and trolls,
any rule that would ban potential scammers could be potentially abused.
That's an excuse, and it's one I've been hearing for years. Don't make a rule because it can be abused? Then why make any rules whatsoever? They can all be abused, bent, loopholed, you name it.
Anyway, hopefully OP figured out that if he wants to warn people about this scammer, he needs to create a proper thread in the Scam Accusation section instead of posting repeatedly about it, which is against forum rules.