It's genuinely just people feeling the need to "pick a side", and it's unhelpful. Just makes the fans look like clowns.
Bluesky's got the same vibe as early Twitter (for now). That's awesome. Mastodon / "the fediverse" can take some time to streamline onboarding so when Bluesky gets sold to Mussolini's ghost Mastodon will be ready to take the reins.
I don't know enough to tell whether or not this sounds plausible. All I know is that the Bluesky team is selling it (to me) very dang well. The app is quite solid as well, I can't lie.