Words spread fast these days. How do you think did the Lazarus group hear about Blender, Tornado Cash, Chipmixer, Sinbad, and others? Bitcointalk.org? I don't think so.

It's not as if this forum is the last bastion for all these players, not even in the surface web. And the surface web isn't probably the playground for the likes of this group. The deep web and the dark web are a wider playground for them. I think news about a new mixer would spread pretty quick in those areas.