i'll have to look into how they have it set up a bit more detail. i don't just assume it is a scam. even something like bisq, the seller has to send their btc to an address out of their control. and trust the people that run it to do the right things...
The seller can find a trustworthy buyer, though. There are also several measures that protect you somewhat from getting scammed.
no one just wonders on to a site like that and starts buying bitcoin with paypal. it's either some or all of those things or they are trying to scam.
Are you saying that DEX users are mostly scammers or am I misunderstanding here?