Earlier quoted context omitted.
The top decentralized exchange, Uniswap, has overtaken the top centralized exhanges in liquidity depth for several major trading pairs: https://uniswap.org/blog/uniswap-v3-dominance So there is a world where centralized exchanges have far less relevance than they do today.
Is it me or "decentralised" almost always means "crippled"? The critical function that exchanges have is to allow people to buy and sell tokens. Decentralised exchanges can't do that. They only allow trading a token for another token.
In this context Circle is still a centralized party that's necessary to interact with the off-chain banking world. But Circle has much less room for chicanery than a traditional centralized exchange. There's no opportunity to front-run, insider trade, liquidate your customers or anything else that OP brought up in the context of centralized exchanges, because all Circle is doing is filling the very simple task of converting 1.00 USD to 1.00 USDC and nothing else.