Texas very specifically swore allegiance to the union and gave up — specifically — the right to secede, after that. That was one of the conditions of coming back into the union.
It’s just the way history went...
You sidestepped my point. Allegiance is a two way street. If the federal government is destructive of the ends of life, liberty and the pursuit of happiness, then it is in violation of the compact that established said government. There are a couple of options. The government can be abolished or its form altered. Secession is another way that allows other states to remain under the rule of the existing federal government if they wish without destroying the government.
Your position is essentially Barack Obama's position: "I won."