I am a strong believer in the right to privacy (even if some people take it what I believe to be too far), and a centralized mixer has the potential to enhance privacy. Also, however, mixers have the potential to give nothing more than the illusion of privacy and highlight your transactions to governments and other nosy people.
I agree. Anyone who uses a mixer should consider that they might be a honeypot. And that's why it makes little sense for a real criminal to put these services above Monero and coinjoins, which are trustless.
There tends to be a good amount of coin that flows through the various mixers originating from criminal activity. This is why governments have employed resources into shutting down mixers and finding their operators.
Sure, if mixers can be the cause to shut this place down, no matter how sad it might be, forbid them. It just makes little sense from a government's perspective. If I was a government official, I would want such services to run, because they would be central point of failures that I can go after. Forbidding them would push everyone (especially criminals) to decentralized, trustless solutions which I cannot control.
Governments are going after centralized mixers. I would question the legality of the government running a mixer as a 'honeypot' for more than a short period of time, although they can seize any logs the mixer was keeping, regardless of any public claims to the contrary.