It's perfectly distinguishable, because Twitter uses Twitter trademarks and quasi-trademarks, e.g. the "Search Twitter" box, the "Tweet" button, the little blue

It's perfectly distinguishable, because Twitter uses Twitter trademarks and quasi-trademarks, e.g. the "Search Twitter" box, the "Tweet" button, the little blue bird logo, while Bluesky uses Bluesky ones, e.g. "Welcome to Bluesky". Everything else is so generic that it doesn't represent brand identity. For example, Facebook uses a lot of blue in a similar three columns layout too.