Suppose for a moment, for the sake of argument, that any people anywhere have the right to secede. Any town can secede from the county, any county from the state, and so on. How would that right be affirmed? In a court of law? Or by rebellion and war?
Every president from George Washington stated clearly that they would oppose secession. So the Southerners knew war was coming, just as they knew that they’d force out union troops with violence. Johnny Reb rolled the dice, and he lost. Biggly.
One need look no further than the Free State of Jones for the answer to how any hint of secession would be greeted by the slavers.
Whether this idea applies to smaller components of a state is not at issue here. In 1776, it was full blown states that seceded from England, and in 1860, it was also full blown states that seceded from the New York/Washington DC corruption cartel.
So no one is bringing up pieces of states to which to apply the idea of secession except for you, who is attempting to discredit the idea.
Now I will point out to you that Lincoln, in complete contravention of a specific clause in the US Constitution which prohibits states from being formed out of the territory of existing states without permission from that state's legislature, approved and supported the piece of Virginia which became "West Virginia", by seceding from a larger state.
I believe this puts Lincoln on the side which says it's okay for counties to secede from a larger state.
Indeed, he argued for this very thing in his speech to congress in 1848.
"Any people anywhere, being inclined and having the power, have the right to rise up, and shake off the existing government, and form a new one that suits them better. This is a most valuable,—a most sacred right—a right, which we hope and believe, is to liberate the world. Nor is this right confined to cases in which the whole people of an existing government, may choose to exercise it. Any portion of such people that can, may revolutionize, and make their own, of so much of the teritory as they inhabit. More than this, a majority of any portion of such people may revolutionize, putting down a minority, intermingled with, or near about them, who may oppose their movement. Such minority, was precisely the case, of the tories of our own revolution.
But history clearly shows that he only believed this when the principle worked in his favor, and completely disavowed this principle when it worked against him.