Ah, I missed your last sentence. Either way, though, I still think there is a benefit to banning anti-vaxx content from general-audience platforms in that it stops people who are not necessarily seeking out anti-vaxx misinformation from being exposed to it in the first place. A great example of this strategy working is Reddit. When they ban a hateful subreddit (like r/fatpeoplehate) it tends to noticeably improve the quality of the discourse on the site in general for a period afterwards as people who were drawn to join Reddit just to be hateful will have less reason to be on it and also because fewer "ordinary" people are exposed to those hateful ideas limiting their spread within the "general" user base of the site. I believe the same approach works equally well with misinformation movements.