Casinos play it safe, they dont want trouble from the governments and they dont want criminals to use their site as an intermediary.
So they allow people to run without KYC on signup because they want more people to get into the habit of gambling but when a certain trigger is met, the account gets flagged for KYC/AML procedures.
They are only saving their business and to keep it running they do these things. It is here to stay and it is better players get used to it.
it has become a common thing in businesses when customers are given convenience to attract their interest in using the services they provide, but when there are special requirements that need to be met by the business, then they will charge users more for them to comply. that's why it's important for users to know the regulations of the casino they use and what the kyc regulations are on that platform. don't let an incident happen when a user wins the jackpot but they are tripped up by a kyc problem and the casino alleges that the account is illegal and they have no obligation to pay the reward.