Bluesky is really lagging in user adoption because the name itself implies some sort of political divide, and from experience, it seems that it's an echo chamber where "right" activists are getting demolished at the first occasion, I wished it would have a mix of people and opinion.
no one really knows, when broadcasters started using party colors it was all over the place and they settled on blue for dems. i guess its because neither party was socialist so there was no association with red like in europe.