I think you've hit the nail on the head right there.
The casino has considered all play with the first deposit, even after bonus removal, as subject to the first deposit bonus terms. So, the OP was expected to withdraw, and then deposit again.
It says that if any other games except slots are played with the deposit/bonus/winnings/comp points etc then ALL winnings are avoid, which is a frightfully bad term.....not to mention the 20x max cashout.
Personally, I wouldn't play there with VWM's money. Its one of those casinos that (IMO) deliberately makes the terms hard to understand and follow to trap the unwary....and in.this case, I would think they'd trip up the odd seasoned player too.
However, in saying that, the time to decide the terms are terrible and that you don't want to be subject to them is BEFORE you play....not after you've been caught by them. By his own admissions, the OP did not read ANY of the terms, so was bound to be in breach of them given their excessively stupid and predatory nature.
Bottom line is that the terms are awful, BUT the OP agreed to be bound by them anyway. We NEED to look past the amount and consider the basics of the situation. You can't start making exceptions for bigger winners, as you will haveffraudsters "accidentally" playing a couple of hands of BJ to boost their bankroll and then referring to this case, and rightly so, to insist their winnings be paid.
The lesson here is ALWAYS READ THE TERMS. Oh, and stay awqy from Crown Europe.