You are correct - barring mental illness - everybody knows that there are some things that are foolish and / or irresponsible to joke about about and may not pass without a consequence.
The arrogance of Shkreli is absolutely astounding considering he is still waiting to be sentenced.
Everyone (including himself) is assuming he'll get a relatively light sentence because that's what a regular person would be expected to get in his position. But a regular person convicted of a felony would have the common sense to show contrition and remorse even if they didn't mean it.
Shkreli can get up to 20 years based on what the judge feels appropriate. And this judge just showed she doesn't view Shkreli as a regular first time felon.
It was reported that he seemed uncharacteristicly quiet and serious when he was ordered to prison today. I wonder if he's starting to realize how badly he has screwed up. If not I'm sure he'll get the idea when he gets sentenced to spend years of his life in prison.
It doesn't help that the guy's no Schwartz or Snowden. He's not defending our rights, or revealing the erosion of our rights, nor saving puppies. He's known for being a jackass. And we all like a jackass until it hits the fan, and then we all collectively back away slowly.