When you enable products from Customized it will automatically create those products in your Shopify store. These products have a product type of "Bare Product".
Since you don't want your customers to add those products to their cart without going into the customizer we recommend one of the following:
1. Hide those products from your collection pages.
2. (Recommended) Update your theme to replace Add to Cart button with a Customize button. For instructions on how to do this follow the "Template" KB article to update product pages.