Signature campaigns give sites credibility. So does advertising on this forum through paid ads. The fact that Theymos denied Betcoin.ag from advertising on this forum is totally relevant information that should be considered when making your own opinion on the situation. But in the end, we each have our own opinion of the situation and have the right to leave whatever trust we see fit.
Just a small point. Theymos did not accept ads from bitmixer. But Bitmixer's signature campaign is alive and kicking.
The forum did carry ads of Bitcoin Black Friday, which turned out to be a scam.
So we shouldn't be linking everything to the forum's ad policy.