Some products i cant add to the shop

Hi, if i look on the normal shop there is like breathing shirts, but i cant find those shirts to add to my own shop? Why is that?

Because our goal is to print 100% digitally: and the breathable shirt isn’t printable in digital direct. Therfore this product is not included in the product range which we offer for our partners who sell via their own merch shop or the marketplace (’re currently looking for a suitable alternative which can be printed in digital direct.