https://the-federation.info/platform/73 says for lemmy we have: 1,073,211 Users
It also says that: Last month users: 38897
Which is 2 orders of magnitude of a difference. If you look at the list of instances there ones like https://the-federation.info/node/details/48405 which have 50k users and 10 active last month users.
That means almost all of the 1 milion users are fake users.
I’m seeing people celebrating every 100k users every couple of hours without realizing this.
And part of what led to lemmygrad in the first place was subs like /r/Genzedong being banned. I think the kinds of people who seek a new location after their sub is banned are much more likely to be in the 10% group who comment and create content. Besides that, the political nature of lemmygrad (and the fact that all those users are likely on the same page about a lot of things) leads to a much more engaged userbase.
In short: lemmygrad is in no way a representative example/sample