Why are you surprised by that? Mastodon is older, a lot more ironed out (in its own quirky ways), actually open to the public, and bot-friendly. Of course it's orders of magnitude more popular at this point in time.
That said, even though I'm rooting for Mastodon, I would not be shocked if Bluesky catches up very quickly. In any case, any of the two is an improvement over a locked down and thoroughly broken Twitter.
Right, Blue sky is invite only, and has just started out. And like you, I strongly prefer Mastodon, but if Blue sky helps organize us into a post Twitter world so much the better.
That said, even though I'm rooting for Mastodon, I would not be shocked if Bluesky catches up very quickly. In any case, any of the two is an improvement over a locked down and thoroughly broken Twitter.