It does seem to be the case that a lot of the time, a casino / sportsbook will use KYC as an excuse to keep winnings, but more often than not they will at least let the player withdrawal their deposit. Its important to distinguish this ("winnings" as opposed to "winnings + deposit") because keeping a player's deposit due to "KYC failure" is a big no-no, and shouldn't be normalized in this industry.
This is a great point and the thing that bothers me the most. There are a lot of cases where sportsbooks are taking both winnings and deposits.
That was not the point I was making. There are not "a lot" of such cases as casinos / sportsbooks that do this will quickly be labeled scams and won't last. If there are, the majority of such complaints aren't being lodged here on this forum.
So they keep the funds including the coins you deposit?
No. Most casinos don't do this. I mean, if you lose, then yes, they will keep your deposit.