Bitfinex and some other exchanges list their crypto prices in USDT and most people trading on their platform probably don't realise this is not dollars. So there's your guaranteed demand. As long as those buyers HODL there is no pressure on USDT.

If they are people who are being defrauded into believing that they are selling bitcoin for USD when they are actually selling it for USDT, then yes we should be worried because fraud is a crime.