Also, there are more things that can be related to "mixing". One of them is called "Silent Payments". Another thing is called cut-through. Because it is possible to send Alice->Bob->Charlie as two on-chain transactions, and have a service, that will batch it, and put Alice->Charlie into the final block. Is it called mixing or not?
No because Silent Payments are not seized by the Feds. Mixers are centralized websites which do get seized. Theymos is banning mixers because they keep getting targeted by law enforcement, not because they are used for criminal activity (otherwise all scammers and Ponzi schemes would've been banned from here a long time ago).
same with full-rbf.