This, basically.
The economic system of the US (and of all modern western democracies) is based on capitalism, but it has never been based on pure capitalism. It has always been a mixture of capitalism and what the anglo-american world tends to call "fair play." That's why contract terms are sometime thrown out by a court; it's why ambiguities in insurance policies are construed against the company; it's why we have a lot of consumer protection laws; and it's why we have anti-trust laws.
(As an aside, it's also why Russia had (and is still having) a hard time transitioning to a modern civil society - it's a lot easier to institute capitalism than it is to institute the moderating principles of fair play.)
It's the violation of the "fair play" principle that has caused most jurisdictions to establish anti-scalping laws: the idea is that if a company offers tickets to the general public, these tickets should not be bought up en masse by scalpers and resold to the public with a price hike. Particularly where the shortage of tickets is caused by the scalpers buying up all the tickets in the first place. (See the Miley Cyrus ticket scandal for a good example - tickets originally offered at $30-$60 became unavailable at any price less than $300, which was particularly hard on her youngish fans without much disposable income).
This is why, intuitively, people don't like the Apple scalpers. Apple set a reasonable price for its products and offered the products to the general public at this price. Of course people are outraged if organized scalpers buy up everything available and your only option is to pay a multiple of the msrp.
It is also - as a matter of economics - highly inefficient, since the only service scalper's provide is to mitigate the shortage that they themselves caused. The analogue is setting someone's house on fire and then charging them to put it out.