This is what is happening in the San Francisco rental marketplace, right now.
As for buyers (advertisement buyers) belonging to a group that evidently was colluding with various buyers to induce their wider membership to exclude a subset of sellers (websites) because of their political leanings?
Maybe this is just activist "boycotting". If every ad buying company in the organization, and every agency was aware that they were all trying to penalize websites that held certain opinions, that should be fine: It's just the "Anti-Conservative Ad Buying Club". No harm, no foul -- Just baddies like X, Daily Wire, Zero Hedge, etc. get hurt.
But, it doesn't appear that everyone involved knew that was the game being played. They were just members of an ad industry organization that recommended good behaviour.
If so, then everyone should be OK if some companies join an "Anti Leftist Ad Buyers Club", and boycotts CNN, WaPo, etc.? Right??