This all depends on the situation and who is doing it.

Frankly there is no point getting upset when an 80+ old lady offers a homemade biscuit. Have btdt trying to get them to understand it is not the done thing these days, but they are of the generation where additives etc were not an issue and for some reason they did not seem to have to deal with allergies. They think offering something homemade is a good thing and in basic sense, they are right, better than a lot the rubbish out there.

I have gone off before when we were at a Home Expo. DD1 had wandered to a nearby stand and had come back with lollies. Initially I had no idea where the lollies had come from, they could have come from a stange man in the crowd or she could have picked them up off the ground. So I started yelling at her "where did you get those lollies?" Finally a bloke at one of the stands admitted to giving them to her and I just yelled at him that he should have asked first. Had I known where they came from I would not have gotten angry.