Observers generally experience sad feelings from seeing someone waste resources, and experience anger when someone is taken advantage of, probably because we perceive our risk increasing (in a tribal sense). Soliciting (and receiving) outlandish "donations" from strangers can look like both a waste and a con.

By tribal risk increasing I mean that if Ogg loses his harvest fording the river, now the tribe has to feed him. Or if Ogg is swindled out of his pelt, now the tribe has to worry about him freezing and make sure nobody else falls victim. In context, this is when your uncle Ben donates to some internet personality and then has trouble making ends meet, and you might have to step in to assist him.

A third unrelated explanation is relative value, where the observer might feel upset watching someone throw good food to a dog, rather than giving it to a starving person nearby because the observer feels the starving person is more deserving of the resources than the animal. In context, this is when your uncle Jerry donates to some internet personality instead of using the money to help you or some other more deserving local charity case (not using that pejoratively).