Is there some reason Fox advertisers cannot be contacted to inform them we will buy from their competitors unless Fox changes its ways?
No reason at all. Send them a message. Tell your friends to do the same. But advertisers look at the numbers:
https://www.forbes.com/sites/markjoyella/2022/08/02/fox-news-sweeps-july-cable-news-ratings-as-all-networks-see-declines/?sh=57ee6ea9562f