Because crypto cannot be regulated by the government and the government wants to control crypto which can be used to tax crypto users.
that's just one of the things that makes the government dislike crypto. actually there are some things that make the government dislike crypto, which is the unstable crypto value and is considered to be used as a tool to fund terrorists because crypto has a peer to peer transaction system that makes it easy for people to send large amounts of money without others being suspected.
A lot of cryptocurrency money launders have been arrested, look at the BTC-e case. US law enforcement agencies, as well as China, are always interested in and watching this market. In addition, they are planning to apply blockchain to the projects they need