All of this is true, but I wanted to relate a similar phenomenon that I observed some 30 years ago that might be of interest, or at least entertaining, to everyone here.
In my formative years, I spent a lot of time reading Usenet, which, briefly, is a text-only forum not dissimilar to bulletin boards or subreddits or Lemmy communities.
I frequented one group in particular called alt.sysadmin.recovery. Most Usenet groups began with alt. by archaic convention, and the rest of the name is simply descriptive or categorical. There were groups like alt.hobbies.baking and so on. Again, not dissimilar from (and likely inspiration for) these modern web-based communities.
This group was for system administrators (or "sysadmins") to generally gripe with one another about the difficulties of their jobs, dealing with users on their systems or networks, and similar. One of the rules of the group was that no advice was ever to be requested, nor given. It was strictly for sysadmins to vent. The key point here is that everyone in the group was in some technical role.
What was unique about alt.sysadmin.recovery was that you couldn't post to it. At least, it seemed that you couldn't, because the group was set to be moderated, but had no moderators. If you posted a message to a moderated group, the message would be emailed to all of the moderators on record, who would either delete or ignore them, or apply their stamp of approval for the message to be posted in the group. alt.sysadmin.recovery had no moderator emails configured.
The trick is a little bit technical. Usenet posts are quite similar to emails: they have some "header" fields (like the title of the post, its author, and so forth) and a body. Most of the headers are not displayed directly (which is also true for email), such as what Usenet software sent the message, and so on.
When a moderator approved a message in a Usenet group, their client would append an Approved: header line with some value, like their name, or the date, or something. As long as the Approved: header was there and had any value at all, the message would be distributed to the group.
So the trick was to simply append that header when you posted the message. Since there were no moderators anyway, nobody could ever accuse you of bypassing the system. Bypassing the moderation system was, in fact, the entire point. You had to know enough about how moderation worked in Usenet to post a message to the group.
One of the lasting results was that alt.sysadmin.recovery was never overrun by bots and spam, even as the rest of Usenet became an absolute cesspool through the '80s.
Which brings me back to my point. A few hoops to jump through and a few initial challenges to adoption can go a long way as a filter for who can show up and interact. Of course we would want Lemmy to be welcoming to anyone who will make the community better, brighter, more fun, and more useful... But we can take our time cracking open the floodgates. Maybe that's for the best.