Gambling addiction is induced by personal choice and external factors; but people tend to forget everything when they are drowning into gambling addiction, so I think the casino needs to step in by blocking the person's access to the platform, making self-exclusion automatic when signs of gambling addiction are seen.
Yes, the casinos would definitely block their most valuable customers(gambling addicts) and voluntarily reduce their own income.

Such KYC automatic exclusion system should be imposed by the authorities to all online casinos(both fiat and crypto). The problem is that I have doubts in the efficiency of such system. First, there are non-KYC casinos. Second, a gambler doesn't necessarily need a casino, in order to gamble. Gamblers could just gather around and play poker(or other gambling games, like dice) without the need of a casino as a middle man.