So, of course, is spamming. Retromoderation is a slippery slope of abuse. BI rules are already enforced. Quite right, it isn't. The argument that commericialism is evil dosen't hold much water with me.
Abuse is evil.
Commercialism is often abuse. Therefore, Commercialism is often evil. People advertise in appropriate groups, and that's good. By your policy, you would have to cancel an add for a new book dicussing Sex in Cthulhu literature. Retromoderation makes abuse easy.