Lemmy naturally concentrates unconnected users with similar interests thanks to reddit-style communities. Mastodon follows the Twitter style where you have to find and follow individual users to get their microblog content, and its harder to isolate certain topics or interests except across the entire service via hashtags. Individual users on their own are very uninteresting and bland.
Lemmy has fewer users but they as a whole generate more active content than Mastodon does thanks to community specialization, since the Twitter style posts require some critical mass of users following to generate interesting discussion (something that basically never happens unless you’re already a celebrity)

Ahh oops. I didn’t check instances just saw your display name. Yeah bug beehaw about it, it’s up to them to update because they are way behind the times.

Beehaw is still on an older Lemmy version (0.18.4) that sometimes has issues federating to newer instances running 0.19.2 or .3. Talk to your admins. It’s been out for months high time to update.

Fuck you spammer.

Reporting them rarely ever resulted in any kind of removal.

Oh it results in removal alright. It results in the removal of my legitimate account from the site due to “report abuse” because I reported those obvious bot farms incessantly.

Reddit admins implicitly encourage this sort of bot spam because any kind of Reddit activity shows active users, which means more displayed ads, which means money for Reddit. They do not give one flying fuck about actually reducing spam.