The constitutional definition of treason is taking up arms against your government. Some militia gun nuts in Oregon seem determined to live up to that definition, occupying the headquarters of a National Wildlife Refuge where no federal employees were present.
They are protesting for the right of ordinary people to appropriate federal property in violation of federal law, or something like that. There is no such right, under the U.S. Constitution or otherwise, and never has been one.
My gut reaction, which isn't the policy that I would advocate, but which they soundly deserve, is that they should be offered a chance to surrender with the risk of not doing so made clear, and that if they do not surrender, the Air National Guard should be mobilized to deal with this insurrection by dropping several very large bombs on them and killing them all, to show backbone against armed defiance of the law. It would probably be legal for the President to take this approach if he chose to do so, even if it may not be most prudent course of action for the President to take.
In practice, a more patient and less bloody way of ending their illegal action, followed by arrest and prosecution for every single one of them on charges such as armed burglary of a federal facility, violation of federal firearms regulations, and the like, would probably be more prudent.
Still, they should be punished in some manner or other, and harshly, with each of them doing hard time in federal prison and the leaders put away for at least twenty years or so.
Non-violent protest and armed occupation of federal facilities are not equivalent conduct. Your right to free speech ends when you engage in criminal activity while armed. Indeed, you forfeit not just your right to free speech, but your right to remain alive when you engage in armed criminal conduct.