Because they can... and because they are not a real distributed platform... =)
This will bring more attention to DEXes too, in the sense of... "they" (the regulators) will try to enforce DEXes to also do KYC/AML, and then it is when things will start to heat up and be interesting... because if the code get's spoofed by anti-criminal laws without the "consent" of the community.. then I would say that that code is NO more... due the simple fact of how distributed open source software works, and how decentralization inhibit the common laws to simply apply.
Anyway... a hole new fun to watch and learn. I am eager for it.