Funny, because I just read that and was going to comment that was the one part I don't agree with: the statement that these guys don't know or care about the Constitution. (I do agree it probably has nothing to do with who is in office. This has been progressing in 1 direction for decades).
I don't know any of these men personally, but I've listened to arguments from Bundy and some of his associates. Their interpretation of the Constitution may differ from the courts, but they make some valid points. The western states should have never been established with this level of federal land ownership, and that is a constitutional issue. No one really addressed it because it wasn't originally done with the intent of the feds acting like the government itself owns it. The government was more of a land manager before. The locals settled it with grazing and water rights, and that was akin to ownership. Now that it's being treated differently, it appears to have been a mistake to have ever made so much land "public land".
Particularly when Federal ownership of land is intended for structures, armories, military bases, etc.
"To exercise exclusive legislation in all cases whatsoever, over such district (not exceeding ten miles square) as may, by cession of particular states, and the acceptance of Congress, become the seat of the government of the United States, and to exercise like authority over all places purchased by the consent of the legislature of the state in which the same shall be for the erection of forts, magazines, arsenals, dockyards, and other needful buildings" (Art I, Sect. 8, Clause 17)