to advertise on your board and one of their main offerings of value is rumors.

What is the difference in that and allowing porn sites to advertise here so long as they don’t post the porn here?

Nobody is saying you could or even should control what they post I their website, but that is clearly a main selling point for CC. You can choose not to let them advertise because, like porn, what they host in their webpage isn’t up to par with CB standards.