Same here.
Anything worn out enough that *I* wouldn't buy it at a thrift store, either becomes rags or goes in the trash.
I only donate stuff that's clean and intact.
Having worked in a thrift store, about 80% of the clothes donated was deemed not sellable and is tossed in truck and shipped off to a place in PA where they do this type stuff in the article.
If you place great stuff in one bag and lightly used in another and let them know which bag is which it would save them time. They look for wear, armpit stains, neck stains, tears and other stains and smells. :-)
I am not sure how/if they would take donations at this time.