It doesn't have to block you from seeing the product. Some e-commerce sites let you enter a zip code on any page to get estimated shipping prices, but don't require you to. Some let you enter a zip code as soon as you've added something to your cart. Some don't do estimated shipping prices at all and don't give you any idea how much shipping will be until you're at that step of the checkout flow.

Fair enough. I suppose I'm just used to what I'm used to. Shipping prices only seem to be something surprising nowadays with Amazon. Before that, it was accepted and commonplace. I wonder if that makes it a dark pattern now.