Which retailers are doing that? Have you objected? I know I would. To me, that is like asking for ID when using a debit card.
Shaw's Supermarkets in the Boston area. I have objected and told them this is ludicrous and not how Apple Pay is supposed to work. You are forced to go into the settings of the card in Wallet and provide them the "device number" so they can complete the transaction. Takes longer than just swiping your card.
I sent feedback to Apple Pay support and was told that some retailers are forced to do this based on their POS system and that I should reach out to Shaw's directly.