Pick and mix sweets are behind covers which are lifted and fruit and veg are normally washed/peeled before eating. I'm quite happy to lift up a lid but a donut sitting on an open shelf at head height, nah.
It probably goes back to a barbecue we did for lots of our neighbours 10 years or so ago...
On the other side of the scale you always see bread rolls and cakes/cookies on the shelves with no packaging, I would never buy these after 1,000 customers before me had coughed, sneezed and touched those food items. I'm amazed supermarkets can sell these foodstuff like that.