The issue is that those policies drive prices up globally, and the article touches on that exact point. Sellers have to absorb Amazon's fees while being required to keep the same price. As a result, their sales outside of Amazon have to factor in those expenses, which drives up prices for those products in general. Even if someone could sell that product at a lower price outside of Amazon, they won't lowball themselves and would rather improve their own margins.

Then, in the EU, you have to factor in fluctuating currency exchange rates and sales tax/VAT set individually by each country. This is another issue altogether.