I need a clarification here... so some guy has some balance at Stake. And that balance mysteriously disappears one morning!!! After that, that guy complains and asks for a refund?! Well, this is something new from scammers!

You seem to have misunderstood the issue here. The gambler's balance didn't just magically disappear. Stake froze his account and siezed his funds due to which he created a scam accusation thread against them.
The Stake team is currently investigating the issue. We are talking about 200 grand here which is why this will probably take time to get completely resolved.
We don't know the whole story yet but Stunna already replied on that player's thread and they are investigating his case. If the player is confident that he did not violate any of the terms and conditions of stake, for sure, he will get his money back. This is the site where you can see huge amount of money used in betting, and I don't think they will ruin their credibility if it is the fault of the site.