I understand what you are saying and it is perfectly fair, but I said "why not also manufacture in Europe or China"

If you can't sell into Europe or elsewhere because of taxes or delivery charges then you lose nothing by also manufacturing elsewhere.

However, I applaud what you are doing.  Bitmain's U3 device used items that the home miner could easily source for themselves making it uneconomic to ship.  Do what you do best of all.