How does having a really tightly controlled and/or lengthy invite period translate into the user base being of one particular political viewpoint? I'm not seeing the causal link. Even if I take at face value your claim that "only really tight knit subgroups and subcultures found their way in," I still don't see how these subgroups or subcultures would necessarily have the same political views.

Well it self selected for left wing ones.

My point is normal people who aren't extremely online and part of 10 Discord servers with an internet friend network who can hook them up with an invite didn't get into Bluesky. Instead the people who, well, did, got the invites. Obviously the extremely online right didn't because they had other places to go and weren't welcomed by the bsky admins.