Oh, that's not a possibility. The part you don't understand is that in Bitcoin you can't tell which transactions are people giving money to
themselves and which ones are actually giving money to other people. So if Coinbase wanted to block transactions from, say, medical marijuana dispensaries ("criminals") they couldn't just block transactions
directly from the dispensaries' known addresses; they'd have to block transactions that drew coins
indirectly from the dispensaries as well. That would mean that your transactions could get blocked by Coinbase even if you weren't a dispensary, but because you had sold services to a dispensary in the past, or to someone who had sold services to a dispensary.
To avoid this risk, you'd have to somehow get access to Coinbase's blacklist of dispensary addresses—maybe they'd publish it—and blacklist them yourself. Pretty quickly you'd find you couldn't accept coins from anyone who used a mixer or any offshore exchanges, because all of them would receive tainted dispensary coins sooner or later. You'd probably find that a lot of the Bitcoin you thought you already had was tainted, too, or would become tainted later as new addresses were added to the blacklist.
(Also, presumably any published address would become tainted pretty quickly; anyone could buy some tainted millibitcoins and send them to it, and people in the tainted economy would have an incentive to get as many Bitcoin owners as possible on their side of the fence. So everybody who accepts donations by publishing a Bitcoin address would get their donations tainted: camgirls, libgen, sci-hub mirrors, Electrum server operators.)
So basically this kind of attack on fungibility would destroy most of the value of Bitcoin for anyone who was participating in the attack. "Simply choose not to accept transactions from the smaller set of addresses" isn't a coherent alternative.