No, the customer is being charged the tax, but on the assumption your price is tax-inclusive. If you usually sell with a receipt rather than a sales invoice, change the price in the inventory item to include the tax. If you sell both ways, remember to edit the unit price when you sell in the fashion that doesn’t match the inventory item definition. Remember, almost everything can always be edited.
The request to have a tax-exclusive option for payments and receipts has long been in the list of Ideas: Tax-inclusive option on cash receipts and payments. You will notice I am the forum moderator who not only put the suggestion into the Ideas category, but wrote it in the first place. So in telling you how the program works, I’m not defending it, only explaining it.