I have been here for going on the 5th year. There have been several times another forum has come up. When this happened, there were only negative comments toward those forums. The majority of these posts from TPU members were saying other forum members were assholes or trolls or the mods were abusive.
TPU is not blacklisted, every other forum than your own is blacklisted. This applies to everyone.
As long as you've been here, I am surprised you haven't noticed the same.