Some don't like to submit KYC since they want to protect their identity. They can't afford to expose their details because some maybe a well known guy or maybe they are also don't want to get any possible problem regarding on hacking or any related on financial issues which might happen to them if they don't became more careful to give their personal details to anyone. We can't force people to just accept this KYC thing since its still up for those people if they want to continue or just quit if KYC will be implemented to all casino exist in this forum.
Anyone has the right to leave the casino if they really object to the KYC requirements which they may not like because they want to hide their identity to become an anonymous gambler, but after all playing in a decentralized casino is also not safe even without KYC, it all comes back to the wishes of which gambler they choose and make convenient, if I'd probably prefer to play at a big casino so even if they asked for KYC it was no problem for me.
KYC has always been a subject of debate that will never end in casinos, many complain about it and many consider it something normal, but playing anonymously is also not always safe, it all comes back to the gambler's choice