It's literally on their border and the history is akin to if The South established its own nation state in Cuba after the Civil War and China became its ally.
At least admit the double standard. I don't mind realpolitik but it's so tedious when it's not plainly stated and there's this veneer of civility.
Yes, the US is allowed to do whatever it wants to in South America. No, other nation states don't have a sphere of geographic influence if the US doesn't want them to.
Taiwan has been self governing for longer than almost everyone that lives there has been alive. It's also a vibrant democracy.
If you care about democracy and human rights, it's morally reprehensible NOT to support Taiwan. We can debate the ethics of intervening in strongman dictatorships like Venezuela, Cuba, or Iran, but Taiwan is clear.
Cool, and it's morally reprehensible to NOT support drastic action to curb the worst effects of climate change, and start trying our very best to prepare our children and grandchildren for an adulthood where they will be clawing back minor things we take for granted even in today's world of regular continent spanning forest fire smoke pollution.