I don't think the lemmy.ml admins have been coy about it.
If you go to the lemmy.ml home page, at the bottom of the right column is a list of admins.
The first admin's profile banner is a picture of Mao. And the second's profile pic is a photo of Fidel Castro. The other two don't have profile pics that are explicitly authoritarian communist and I haven't had the patience to look through a whole lot of their posts or anything.
Just a couple of Reddit threads (via libreddit.hu) on the topic: one and two. Unfortunately what they link do doesn't appear to be in the wayback machine as far as I've been able to tell.