If the government hate privacy so much why did they leave Monero and Dash still existing? Probably because they are benefiting from it too.
It's more likely that they haven't done anything about them because they are tiny. Also, maybe because there is nothing they can do.
For Dash, I can't really tell their stance with the government, but as for Monero (XMR), they are one of the greatest enemies of the government. Government agencies don't like it even after and before they set out a bounty to try to understand how to track transactions on Monero and a few privacy coins. They see Monero as a threat, but they can't really do anything about it aside from restricting regulated centralized exchanges from listing it.