That doesn’t indicate the seller. This indicates the manufacturer of the product. You won’t see who the seller is until you click on the actual item and it will be listed in the product details. This is NOT being sold by Valve on Amazon.
I bought my Index controllers a bit over a year ago at launch via the Steam Store. The package was shipped from within Canada, not from the US. It came with free shipping and no import fees. I paid the listed price.