Well, which part?
I didn't say that the PRC was legally or morally justified in its view -- only that it was a natural expectation. A human one, I might add, not one limited to the Chinese people, or to communists, or to Chinese communists.
And of course your in law would disagree with my questioning of whether it is worth the significant cost America would pay to actively defend Taiwan from a PRC invasion. It would be weird if she didn't. But, and I say this with sincere due respect to her, just because she's Taiwanese doesn't make her opinion correct about what is in the best interests of the United States. What if she were Tibetan? Or Georgian? Or Ukranian?
Again, I understand an argument that the long term interests of the United States would be best served by an active defense of Taiwan, regardless of cost. I simply disagree and neither of us have a crystal ball to see who's right. I do totally support an approach of US strategic ambiguity regarding Taiwan for now and, accordingly, I had no problem with Biden's agreement that he was willing to get involved militarily to defend Taiwan. Whether it was a flub or intentional is of no matter to me.
But, if I were president when the invasion began, my priority would be on providing as much assistance to the Taiwanese without exposing US forces to significant harm...knowing full well that such decision would likely mean that Taiwan would fall to the PRC (and that my political career would be over and my legacy forever tarnished).
Ask me about Japan or any other sovereign nation in the area other than Taiwan, and I'll give you a different answer. Imo, China and Taiwan are a special case.