The difference is that in a lot of cases, the drugs in question were relatively cheap to begin with. Like the pain relief drug Vimovo, which spiked from $1.88 to $23.86 after its patent was purchased by a company called Horizon Pharma. Those numbers don't look as outrageous, but seeing as how it's a drug that's used for general pain relief, chances are it's way more commonly used in hospital settings than an antiparasitic like Daraprim. Either way, it's a company maximizing profits on the back of the general public's need to feel better. That's gross.
Of course, the other difference was Shkreli himself. This was a year characterized by people publicly embracing the most extreme aspects of their thought processes and refusing to back down, no matter what criticism came their way as a result. It worked (and is still working) terrifyingly well for Donald Trump, who just gets more popular every time he puts a face to your drunk uncle's most heinous holiday outbursts.
Martin Shkreli tried to do the same thing. He pointed out that maximizing profits for his investors was what he was hired to do, and refused to budge on the price of the drug that made him infamous. He was also obnoxious as shit on Twitter, engaged in a weird flame war of sorts with Bernie Sanders, and broke the hearts of emo fans the world over when a picture of him wearing a Brand New shirt made the rounds online.
That part was pretty funny.
His final (for now) act of awful, weirdly enough, actually happened before most of the world ever heard of Daraprim. Remember that Wu-Tang Clan album that they recorded and swore they'd only sell to a private buyer for a minimum of $1 million? Well, back before the drug pricing scandal, Martin Shkreli agreed to be that buyer. That news finally broke in early December, and once again, Shkreli acted like the biggest piece of shit possible over it, vowing that he was saving listening to it for a rainy day, but would reconsider if Taylor Swift wanted to hear it. He also took to YouTube to post names of other artists he'd consider paying a huge sum of money to in return for an album that only he could own.
Rather than run the risk of living in a world that isn't allowed to hear every Gucci Mane song ever recorded, the feds decided to pull the plug on his shenanigans and arrested him for securities fraud, alleging that he ran a "quasi-Ponzi scheme" at a previous company.