My position is the same as the founders articulated in the Declaration of Independence.
States have a right to independence, and they do not have to justify their reasons to those people who wish to deny it to them.
Of course you don’t care because it doesn’t support your argument.
The Declaration of Independence is based on the natural law of the right of rebellion. Nowhere in the Declaration or in any of the founders writing do they claim England should just let them go. Just as there is a natural right to rebellion the existing government has a natural right to defend itself and try to suppress said rebellion. When you invoke the natural right of rebellion you must still win your independence by force of arms. Even Lincoln acknowledged this when he was a congressman.
People, including you and me, also have a right to look at the causes and reasons put forth by both sides and make a moral determination on who is in the right and who is in the wrong.