You should say that asking for KYC verification for a decentralized casino project is not necessary, when it comes to centralized platforms, they have licenses and would definitely require KYC to comply with regulations and AML laws imposed to prevent the businesses from anti-money laundering and other such illegal activities.
When we talk about traditional casinos or sportsbooks, the reason why they didn't require KYC is that there was no such concept back then, KYC was introduced just recently after the rate of illegal activities and cheating was on the rise.
I think people understand that casinos due to their license and the increase on the number of users they serviced thanks to the pandemic are going through a period in which governments are giving them more attention than ever, and as such they need to ask for their gamblers to identify themselves more often and to be more strict on their requirements, but a casino that is supposedly decentralized should never ask for that information, and the moment they do so then we as gamblers lose any incentive we may have had to play there.
Obviously, online casinos were never so popular, but it was only after Covid-19 hit the world and there was pandemic and everyone was in self-quarantine, all public places including casinos were closed down and that is when the rise of online gambling started, people started to find ways to do their usual activities, gambling being one of them, so they stumbled upon online casinos.
When people started paying attention to online casinos, crypto-gambling platforms started to become famous, and ultimately, they have become a new trend now, and that is the reason why authorities are always behind them.