“Where in the constitution is the federal government given the right to prohibit any citizen, including felons from owning firearms? At best it’s a state issue.”
When you’re a convicted felon, you lose a lot of your civil rights. It’s not just your 2d Amendment rights that are forfeited. Same with the Baker Act. The whole purpose of the Baker Act is to provide a mechanism where a court determines that you are so insane that they need to lock you up. If you’re so insane that they can lock you up, then you’re insane enough that they can take your guns.
If a person is too insane or criminally inclined to be trusted with a gun then they should not be released. The beliefs you stated have no basis in the Constitution, only the bastardization of that document that has happened in the past 50-ish years. At best it would be a state issue under the 10th amendment.
The court signs a warrant for an exam that can last no more than 72 hours.
That does not mean one is crazy. In fact, the exam probably proves they aren’t.