But it leads me to another technical question: Can CoinJoin participants censor other potential participants of their CoinJoin? I.e. could there be CoinJoin transactions where a "tainted" input would be rejected by all other participants, so the often unfortunate owner of the tainted UTXO can't find a CoinJoin to integrate their transaction?
It's possible, sure. But if there was a potential coinjoin with (say) 50 different participants, and I was holding the whole thing up because I didn't want my UTXOs to be coinjoined along side some other specific UTXOs, then the rational action for everyone else is not to ask me to share a list of the UTXOs I don't like and then double check all the other participants against my list, but rather to simply exclude me since I'm the troublemaker here. This becomes even more evident if there were two or three people like me who all had different lists of UTXOs they didn't want to be associated with.
People who don't want to be linked to other specific UTXOs simply wouldn't use this specific coinjoin protocol. Everyone else who does not buy in to the provable nonsense of taint could use the protocol freely.