Probably because they are new? The older the plant gets (and therefore the fabric pot starts to look a bit on the sad side), photos generally don't include pictures of the pot since the main focus is the plant itself... therefore, you're just not seeing the salting up of it - that thin haze of white that pretty much all fabric pots get to some extent by the end of the grow. I've only tried to re-use one set of fabric pots and that was a real pain in the ass and, frankly, not worth my time.
:-D