why are you showing me excerpt's from PRC's constitution? Yeah, China claims Taiwan the same way Russia claims Ukraine, I dont care what the aggressor imperialist country thinks, I care what the people within the territory think. And what they wanted was to host a US official in their territory, and then China decided to threaten them. I get the impression folks in your circle have nothing but disdain for the people in Taiwan and dont care what they want.
That UN vote is not about Taiwan being a part of PRC, it's about who represents 'China' in the UN.