You pegged it Mercat! I have two of those “reusable” bags. I use them to carry documents or tools. I would never put food in them. No one washes these things, I sure don’t.
CDC records that parts of California with bag bans have higher incidence of salmonella, because the cloth bags are dirty.
Most of those bags fall apart if you wash them. I have a couple of them and like you I use them to carry other stuff. Actually I think I’ve used them lately to pack things in to donate. I’ve been cleaning closets and usually have a bag or two of stuff to donate every month.