By now, I think this mixer of a thing should have been put behind us, theymos will do anything that will make people think he didn't think it well before he acted, and for me, that decision was a perfect one. The repercussion he guarded against is different from the end-user discussion, but those who are advertising them.
Is it not better to safely advertise here and not be known to advertise what the government is clamping down on? Many must have missed the big money from mixers, but it can't be compared to shutting the forum for it.
I personally don't think the government would shutdown bitcointalk because some users, on their own, advertise for mixers on their signatures. But you never know...
Worst case I think just banning ANN threads would be suffice, because then you don't have the excuse of the forum allowing the mixers representatives to have a platform to discuss and maybe "operate" their business (as critics would say). Then allow each user to use whatever they want on their signatures *as long as it's not illegal* (AFAIK, mixers aren't illegal in the USA, where theymos cares the most about laws).
Despite the big mixers' money, how many big advertising outlets do you know that openly advertise for them?
Not many outlets advertise for gambling, porn, as well.
Mixers are very niche (crypto + privacy, two super niche things). The regular joe doesn't care about privacy and many hate crypto. And yes, some mixers were being shutdown exactly because they provide privacy, even for bad actors (like north korean hackers) so that's enough reason for advertising outlets to disallow them... but those outlets only care about their business, not to promote privacy (which I think this forum should look after, instead of bending the knee).