I think a good majority of those of us migrating here from reddit are content creators and/or productive users (engaging in relevant discussion, reporting spam/trolls, downvoting/reporting irrelevant content, etc.).

I think there are most definitely going to be social loafers, lurkers, and harmful users coming over from reddit too. But I firmly believe that the proportion of healthy users greatly outweighs the unhealthy users in this influx of users from reddit.

It's the trolls, mindless idiots, hateful, anti-intellectual, unproductive and unhealthy community members who are content staying on reddit, and are glad to see us leave.

I think Lemmy being new and unpolished will also help sift out unproductive/unhealthy users. They'll arrive and see that Lemmy/the fediverse is still in its infancy, and they'll likely rather just stick with reddit because it's more convenient.

I think the proportion of unproductive/unhealthy users here will grow as the site grows and becomes more stable and streamlined. But I think we've got some time to foster a great site/communities before they come en masse.