Though I'm thinking why did Binance remove these stable coins? Are they moving aggressively?
No other reasons, Binance wants to dominate the crypto world. They want their coin, BNB to dominate. They want their stable coin, BUSD to dominate. They have the dominant exchange now, Binance which they know many people are using.
The damage I see about this is that Binance users will later prefer BUSD and not go for the other stable coins mentioned. Binance want more popularity for everything about them.
You sound like dominating is something easy to do, if not other exchanges will also fight to Dominate. Besides, I don't see any problem with binance trying to strengthen their own coin, binance worked their way to the top and still working twice hard to maintain that position.
If the number of users of busd is not up to what they expect, it is very likely they will come up with best way to increase the user base, what do they benefit in supporting other stablecoins when they can easily promote their own.
You can use your usdc in other exchanges, binance did not prevent you. Business is about survival for the fittest, making tough decisions and not playing favourism.