Leaving them out is inhumane to the rest of the society. Is the right of an individual greater than society? especially one who has been violent in the past towards other members of the society either through one's volition or not?

The lawmakers and the public in American in general are not able to digest this correctly. There is no ethical dilemma here. One person who is/can harm another human being needs to be put in a place where they can't cause harm(This includes self-harm as well).