Still, feel you on the retail apocalypse, and how every other new internet darling can somehow skirt taxes or... and the problem is unfixable until right after it doesn't matter anymore. It took something like twenty years for Amazon to start paying US sales taxes most of the time, in many cities Uber's business model was price dumping etc.
Shimano could, were they willing, use Parallel Import laws to prevent European retailers from selling those products in the American market. They've chosen not to. So whether one likes hearing it called a "refusal" or not, I think that's what it is.
Seems like addressing this problem is important. Why is wholesale cheaper in Europe than the US?