I agree. Lemmy Hoste multiple communities on a single instance. This gives room for interaction with people thinking different than you. That's i.m.o. positive.
I learned In fediverse there's much ignore lists and exclusion of servers happening. I'd much rather have users personally choose which communities/users not to see than whole servers being excommunicated for them(unless it's spam servers ofcourse). Excluded Servers clusters(islands) are a breeding ground for mindset that the whole world thinks likewise(because there's no notion of other servers). In my opinion cancel-culture is detrimental to society. Documentary "The social dilemma" has shown that; eg Facebook which, for add revenue, targets info only to users who are already interested. This breeds anti social/extreme mindsets.