If you're talking about Tether/USDT (which is a massive fraud by all appearances), that isn't an exchange. Decentralized exchanges can't just mint more tokens,

If you're talking about Tether/USDT (which is a massive fraud by all appearances), that isn't an exchange. Decentralized exchanges can't just mint more tokens, unless they deployed the token for that contract with an allowance for them to mint it. AKA, the largest decentralized exchange, Uniswap, does have a Uniswap token. But they can't just mint it whenever/however they want, the contract (which anyone can audit) doesn't allow it