I agree with holding terrorists indefinitely, so long as there is ACTUAL EVIDENCE that they ARE TERRORISTS, AND a JUDGE has reviewed everything and agrees their rights aren't violated.
Beyond that, holding people without cause is a fascist act.
I don't know what this act says, but I understand why a libertarian would freak out about it. But, this guy is also a terrorist if he is calling for assasinations of the Prez and his family. He should be held ....indefinitely!