[rglullis]

Because number of subscribers does not mean activity momentum, and recommendations for communities on topic-specific instances are preferred over communities on the "larger" instances.

Lemmy.ml was the first instance, so naturally many people created communities there before. This does not mean that it's still where the anime fans want to congregate. The admins of lemmy.ml also said that they want to promote decentralization so they want as few communities there as possible.