My understanding is that government have problems with anything that is privacy oriented, so I will not be surprised if they go after DEX someday because they do not collect KYC data of their users. Most of the funds stolen through hacks are passed through DEX together with mixers and coinjoin, so I think they are in the same category and in the wrong side of government books. Using DEX may not pose a threat to the users but the operators might be targeted through shutting down and other forms of crackdowns.
They always do, and I can't really blame them for it. Like when the privacy coins got banned, did you really got shocked about it? Think about it for a moment, we are talking about something that allows you to hide your transactions from the government. You may have very good reasons for it, even just saying you want to evade taxes, which almost everyone does.
But you also need to remember, that also means bad people are using it as well. So when it comes to DEX, same logic applies, YOU may have good reasons, but bad people do exists out there and can use it.