Why not tax the negative factors then, rather than the country of origin?
i.e. If the price is supposed to be a lever for labor conditions, why just tax China heavily and not Bangladesh?
Why tax more fuel-efficient European cars instead of American-Built Jeep Grand Cherokees?
And if reducing plastic waste is the priority, why would Trump's day include unbanning plastic straws?
Answer: It's not actually about reducing negative externalities, it's about geopolitics, otherwise it wouldn't be so negatively weighted towards a single actor.
So if the only lever you have to affect consumers is price, then you must factor in the negative factors with higher prices.