You're just asserting that though. There was a study done on the removal of two of the racist/hate subreddits on reddit that indicated a positive affect.
"In this paper, we studied the 2015 ban of two hate communities on Reddit, r/fatpeoplehate and
r/CoonTown. Looking at the causal effects of the ban on both participating users and affected communities,
we found that the ban served a number of useful purposes for Reddit. Users participating
in the banned subreddits either left the site or (for those who remained) dramatically reduced
their hate speech usage. Communities that inherited the displaced activity of these users did not
suffer from an increase in hate speech. While the philosophical issues surrounding moderation (and
banning specifically) are complex, the present work seeks to inform the discussion with results on
the efficacy of banning deviant hate groups from internet platforms."
"In this paper, we studied the 2015 ban of two hate communities on Reddit, r/fatpeoplehate and r/CoonTown. Looking at the causal effects of the ban on both participating users and affected communities, we found that the ban served a number of useful purposes for Reddit. Users participating in the banned subreddits either left the site or (for those who remained) dramatically reduced their hate speech usage. Communities that inherited the displaced activity of these users did not suffer from an increase in hate speech. While the philosophical issues surrounding moderation (and banning specifically) are complex, the present work seeks to inform the discussion with results on the efficacy of banning deviant hate groups from internet platforms."
http://comp.social.gatech.edu/papers/cscw18-chand-hate.pdf