I've seen a few people claim that this only happened because "government interferes with business" and if the Gov and insurance companies didn't interfere there wouldn't be a need to jack up the prices. (Which is the complete opposite. With completely free market there would not be any need to ask for less than the absolutely highest price you think you can get away with.)
Well, no. In a completely free market there'd be other people making pyrimethamine and selling it cheaper than this asshole, because why wouldn't they? Making the stuff is cheap, sell it cheaper than him and you can capture the market.
The reason that doesn't happen in the not-completely-free market is that it's expensive to get the FDA to let you sell your own drugs. For good reasons! But still.
This is not the free market's fault, because this isn't a free market (and shouldn't be). This is mostly Martin Shkreli's fault, plus some blame left over for the system that sets up the incentives this way.