Casinos know that if they asked for this information upfront a great deal of players will not bother... I think casinos keep this information hidden so scammers do not abuse their policies
I agree with the first part and I totally understand why most casinos do not enforce kyc on registration as this will result in them losing many of potential customers. But the reason you mentioned isn't reasonable and some may even consider it unethical since a good service provider has to as clear and transparent as possible with its customers when it comes to their policies.
The fact that KYC means disclosing some of our important information then maybe some gamblers tend to refuse to do KYC. But this is the trend now, even the most reputable gambling casinos have already required KYC, so it’s up to us if we will still gamble on their sites or not. However, the OP might have misunderstood Duelbits rules and policies and so he is not in favor in it. But for most of the gamblers here, even myself, I find Duelbits just fine to gamble.