When it was obvious that the secessionists would carry the day in Richmond, nearly all members from the Western counties of Virginia, and a few from the eastern, walked out of the legislature refusing to participate and formed their own rump legislature in Alexandria. Which is the fatal weakness in your exculpation of Lincoln and the rump faction of Virginians who didn't accept the actions of the other 3/4's of the People of Virginia.
The People of Virginia had the right to reform their government whenever they pleased -- and to secede from the Union, for that matter. Nine guys in a phone booth in Alexandria had no right to call themselves "the People of Virginia", nor any right to attempt to form a government, when the intact government of the People of Virginia was fully functional in Richmond.
States have rights and powers. Dissident politicians don't have the same rights and powers, nor any right to pretend to dispose of same.
So blame the people of West Virginia who desired to stay loyal to the Union. Or blame the Richmond secessionists who pulled their Representatives out of Congress, leaving a an entire region that didn't want to commit treason with no Representatives in congress. Blame congress for allowing those people representation. Blame 80 years of Virginia history that discriminated against the western counties and caused major resentment. Blame people who put on their thinking caps and said to the idiot fire-eaters in Richmond "If you feel no loyality to the national government, why should we feel any loyalty to you?
Blame who ever you want, but it was perfectly constitutional. No one said you had to like it.