That's because spam is an attack on the service. More like DDoS traffic than commentary. It's a matter of operating the site, not policing the ideas therein. "

That's because spam is an attack on the service. More like DDoS traffic than commentary. It's a matter of operating the site, not policing the ideas therein. "Hate speech", on the other hand, is about voicing particular modern taboos. It's inherently politicized and controversial. Banning it site-wide would be little more than moralistic.