1) Send in the police and have people imprisoned 2) Send in the army and have people killed
In practice they have a lot of much softer options because they leverage the basic powers into more subtle ones, but government is fundamentally about who controls the army and the police. Feinstien, like all people in the US Congress, has made decisions that ultimately involve some really, truly horrible outcomes for other people. She lives in a world where horrible things do have to happen sometimes to keep order, even in the more optimistic models of government.
It is unlikely, so say the least, that the implications around civil liberties escape any long-serving politician. The enforcement of laws necessarily sits on the edge of abusing civil liberties. It is more likely she just doesn't want to talk about that.