Not using the tongs is a no-no, both because it is forbidden by the rules, and because you don't want strangers touching things you are going to consume. But if you do not use the tongs, but also do not touch anything other than what you are taking for yourself then it's no big deal on the health front (though as I said, you should - and I do - use the tongs).
I guess everyone is different (deep statement
) but we encounter gazillions of germs out there and at home every day, and while I would not take anything at the QP that I knew someone had touched (and incidentally, would never buy anything from those open salad bars the supermarkets have :shock
, the chances of 'getting' something from handled food in the QP are probably a lot less than 'getting' something from anywhere else you frequent on your daily travels, food-related or otherwise.
On the attitude front, the pax described in the OP needed a swift slap.