I’m not anti-capitalism like the other guy, but I still need to correct your first bit. I’d rephrase it as “People adding value to something then reselling it is the cornerstone of (uncorrupted) capitalism.” “Adding value” can be lots of things, even something as simple as collecting a bunch of related products together in a more accessible, easily browsed format, i.e. what your average retail store does.

Scalping does not add value. It leaches it. You could try saying it adds value to someone who couldn’t be present during the original sale, but it does that by robbing the purchase opportunity from someone else while adding an exorbitant middle-man tax, so there’s no net gain in the system. It shouldn’t matter what platform or legal rules exist. It should be enough that it’s obviously unethical.

The closest I’ll come to saying something like scalping is okay is when someone resells a product forclose to the original price to people left out of the original market.