One question I would like to ask is if mixer campaigns are banned from this bitcoin talk forum will mixers stop? Of course they will try to advertise in other places. If the mixer doesn't stop, it might be better to let the campaign go on this forum.
Definitely, mixers will go to some other place to advertise themselves, and the reason behind banning mixer is that bitcointalk or it's users does not get into trouble for promoting them.
You are right, and the below-quoted statement of theymos is enough for every sensible person to understand and know the plight of the admin. M!xers have so many options to promote their service, this is unless the world government proves that m!xing advertisements are banned. If not, Bitcointalk is a single place out of the host of places, m!xers may not even feel this, they will strategize.
There's someone on the forum already operating and campaigning for a site that will be a third-party bridger between BTT and m!xer. This is part of the point we are talking about, but I don't know if theymos will approve of it if eventually known.
I would prefer to allow them. I don't view using them as unethical, and I don't care about reputation. But this kind of thing is far from the core mission of bitcointalk.org, and the costs far outweigh the benefits.