Why are there policies against insults but not against business advertising?

Most instances seem to be putting a lot of emphasis on their code of conduct specifically in regard to insults and harassment. I'm not against that and i understand the concept of "your server your rules" but i'm just curious to understand why many are so concerned with slurs while they don't seem to care much about big tech advertising here. I'm posting this seeing plenty of GAFAM in the top posts of the bigger instances.