There is more interesting info to be found if you use the link, but I think it is quite easy based on these requirements for US prosecutors to operate internationally because American citizens are served by all mixers and that case can easily be made. They could just find one single person to have used a particular service. Worst case is that a mixing service really launders tens of millions of stolen funds. But I underlined the part that Chainalysis correctly brought up as the major contradiction: KYC + mixing coins makes zero sense.
Yep. But that's the view of one country with about 4% of the global population. Of course there are more, like EU states under MiCa, with similar requirements for any service which stores customers' coins. But in many countries crypto services aren't regulated, and in others (like Switzerland), for KYC to apply there are thresholds which could be respected by mixers without putting into risk their business model. They simply could implement a policy like "only X coins per IP/day", and to circunvent that, you need proxies or VPNs so that would be again an "advanced" technique (and it would be simpler to use Monero for example).
There should be ways for mixers to use geofiltering to exclude users from the KYC-demanding countries. Tor may be an issue there, but normally if a company takes "reasonable" action against being used by customers of a particular country, they should be fine against prosecution from the US and other privacy-unfriendly states.