lemmy.ca seems to be the 6th biggest server while ani.social is 33rd, so whoever created this community on lemmy.ca is actually contributing more to centralization than they would if they put it on ani.social if you’re looking at just instance size. It might be decentralization when it comes to spreading topics around: I understand not wanting all your anime eggs in one basket in case something happens to ani.social, although I myself am a huge fan of the topic-specific instance model.