I think he is saying that of the total interactions he gets he would expect a large amount of hostility to his opinion on Mastodon, and it is also a small population which is available to interact with on platform. Consistent, just talking about the experience and an objective measure. In my opinion Mastodon will be helped by Bluesky adding a paid membership. The worse it is the better for Mastodon, and honestly if people have already started moving out from Twitter to Bluesky they are not locked in yet so moving out again is easier, they already dropped Twitter but Bluesky is not solidified yet.