The probability banning would cause a decrease in revenue (ad-viewing users not on the site if banned creator not on the site) has to be weighed against the probability not-banning would cause a decrease in revenue (advertisers not on the site if banned creator
is on the site). It's all very advanced mathematics, far too difficult for the common man to understand.
Oh, uh, I mean.... "ethics". And "morals". And "terms of service". Yeah, thats it.