I would not be surprised if Altcoinstalks owners/operators take a similar decision to theymos with regards to banning mixer but it seems highly unlikely now for two reasons. First is because the so-called crypto friendly US administration are making decisions. Second is because if they wanted to ban mixers they probably would have done it around the same time but they did not. As a precaution, the owners/operators might consider a ban on mixers or at least keep their options open.
That site wouldn't have any active users if not for allowing them to advertise mixers after Bitcointalk banned them.I can agree that this forum would have a lot fewer users if mixers didn't advertise there, but the forum has been around since 2018 (if I'm not mistaken) and has a small but still active user base that was active even before mixers appeared there. In addition, it's not just mixers that are represented in sig campaigns, there are also a few gambling sites that have active campaigns.
Currently, only three mixers have active campaigns on that forum, the number of logged in users online is around 80+ at the moment, and on BTT around 190. It's not that big of a difference.