From its geographic location alone, the US has had a strategic interest in Taiwan since long before TSMC became the dominant foundry. Nor is TSMC's dominance in that area assured. Not even the most hawkish of pundits seem to think China could realistically invade Taiwan for at least a decade, and that's just considering the logistic feasibility. A decade is an eternity in tech, and TSMC is not so far ahead of Samsung or Intel to be unassailable.

Obviously, yes, if TSMC were to be razed, it would have very significant global economic affects. But people act like it would set the world back 15 years, which is just absurd.