The Ron Paul is Wrong about the Civil War" part is a disagreement -- the "And He Should Be Ashamed" was a little over the top.He just doesn't agree with RP's stance on the Civil War and Lincoln. I wouldn't exactly call what he stated about it as "negative remarks about RP". Not everybody hates Lincoln and hopefully that doesn't become a litmus test in this movement.
But quoting DeVore on the 10th Amendment"
As for states not having the right to seceed, that is obvious, as the United States was created with the ratification of the Constitution hence only a legal dissolving of the same could allow a state to become independent. The states that voted for secession in 1860-61 could have followed the legal route in calling for a Constitutional convention or for an amendment to the Constitution allowing them to seceed, but they chose the route of rebellion and war instead.
Look, I am not trying to take away from DeVore, just to understand where he is coming from on some important issues. These days that 10th Amendment issue is a big point to many people -- especially to Conservatives, Libertarians and to Liberty Republicans.