It "worked" only if the definition is "it removed it from Reddit". As the article mentions, these people did not just disappear or change their mind. They just moved to more obscure places, where they can continue and be evem more motivated, because now they have been censored. And you might still consider this to be a satisfiable definition for "it worked". Out of sight, out of mind. Except that, these people are no…
When the users moved to other Reddit groups, they did NOT exhibit the same level of hateful behavior. some of this was due to better moderation. This contradicts your view that they simply go away to deeper holes away from moderating influences, and supports your point that moderating influences do provide positive influence.
The other key finding is that "bigotry is easy and those who cherish it are lazy". So, merely removing the cesspool removes a place for them to swim, and they often simply don't bother to go find or create another cesspool. So, overall activity is reduced.