I feel that the large number of users is a problem, not an asset. What makes a platform good is the engagement level of the users, not the volume. A user who does not want to engage enough to create an account is not likely to be engaged enough to add significant value.
I moved away from Reddit because I don’t want to be part of one monolithic site, I want to be engaged with a smaller group that has more creative energy. There is no exclusivity clause that prevents people from using both sites and accessing all the content, but having them federated will lead to homogonisation and ultimately destroy what makes this site different. To extend the milk metaphor, we are the cream, mixing us in with the milk will make it richer, but destroy us.
I agree with your comments re: engagement and community. But Meta federating doesn’t impact that. Their users/communities will not suddenly become part of your local feed.
It is not my local feed that concerns me, it is the fact that we will become part of theirs. It will be like when a post is popular enough to make it onto the front page of Reddit - suddenly a post that was crafted for a local community, with users that have a shared culture and background, becomes exposed to a random audience including trolls and bullies who take 2 seconds to judge it and have no barrier to putting on their own comment and starting a pile on.
