I think it's a mix of both. Most of the posts I've read on this thread describe people only wanting clothing that is soft to the touch, and a dislike of anything rough or scratchy.
That can apply to NT, too, but probably not to the extent that AS people will take it.
I can't stand rough/scratchy clothing either, and will not buy clothes in certain fabrics because of how they feel and will frequently remove the tags and labels as they catch on my skin..
LIke most of the posters above, I won't generally buy clothes that are 100% man-made materials (although new fleeces seem OK) so usually stick to cotton, or blends, or occasionally silk if i can afford it.
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Away with the fairies.