Could be case of using VPN due to restricted country or something. Moreover, doing KYC these days is easier than going into physical casino and exposing our faces straight to the public and get recorded on CCTV.
Full KYC due to VPN usage? I don't know about that. I haven't really heard of many VPN related cases where gamblers had to provide full KYC in order to access their account and funds. Most full KYC cases are related to big amount withdrawals.
But those who don't ask Kyc have questionable reputation so I would rather choose what I trusted since it give me more peace of mind while my balance still on their casino.
This isn't true. No KYC doesn't automatically imply questionable reputation in the crypto gambling world.