Because we not only want to pay less for drugs in America, we would like other countries to pay a bit more too and help shoulder the cost of R&D for new drugs and treatments.

An analogy: you live in an apartment building in which every other apartment has rent control. Because of this you're going to pay every extra expense for the entire building.

You could decide to become a rent controlled unit as well -- but the building owners would have less money to improve the building, and it would fall into disrepair.

Or, instead, you could try and find a way to get everyone to equitably share the improvements to the building.