It looks like CZ wanted to dominate the stablecoin world, reason why he is going to stop other stablecoin trading in his exchange platform. Well, it is his right to do so, and I think it is fine since deposit and withdrawal is still available for those stablecoins. Its that if anyone tries to trade them, they need to convert them to BUSD and do the trades. As for me, I don't mind as long as I can still deposit and withdraw it from the platform. It is just an extra step if we wanted to trade with those stablecoins.
I don't think that CZ wants to dominate the stablecoin market. If he and Binance wanted to do that, USDT should also be on the delist from Binance, not just USDC, USDP and TUSD. Of course they have clear reasons why they made the decision to delist USDC, USDP and TUSD, but it's impossible for them to clearly tell their reasons publicly. This is purely a competition. As far as I can see, Binance's policies don't have an overall bad impact on the crypto public, it's just that they narrow the adoption of Stablecoins other than BUSD, which is a minor issue, because we know that Binance is the number 1 exchange ATM.