They want to protect their own reputation too
They would do a far better job of protecting their reputation if they actively fought
for privacy and
against censorship, instead of implementing procedures which do the exact opposite.
But it would also be that, or face sanctions and lose their users, or shut the service down. They simply chose the trade-off, and lose some reputation.
Plus Wasabi isn't just a CoinJoin service, it's also a wallet where people hold some of their Bitcoins.
And yet there are wallets such as Electrum which have been developed for more than a decade without any income source and without even accepting donations.
zkSNACKs have already admitted in interviews (see quote below) that their decision to start censoring their users was because they want to make profit from institutions. This is the driving force behind every decision they are making.
if you, as a CoinJoin coordinator, if you want to work with institutional clients, hedge funds, insurance funds, Michael Saylor, and all these people, well, even if ZKSnacks were not to be regulated, those customers might very well be, maybe because they’re custodians of other people’s money or whatnot. And then these regulated entities can only become users of a coordinator—arguably, I’m not sure—if such a blacklisting is involved.
It then makes logical sense for them. They want to provide their services to institutions who merely want a mixer/tumber, but without "the taint".