The judge forced him to actively troll people, including goading his large audience into physically harassing a presidential candidate? I don't have a position either which way, but judges can consider whether the defendant shows a measure of responsibility and understanding [0] (e.g. remorse). Shkreli was bragging post-conviction on livestreams [1] and interviews that he wouldn't be spending time in prison. Whether people like Skilling deserved more punishment or not is orthogonal to Shkreli giving the court plenty of room to doubt he had recognized what he had been found guilty of.

[0] https://en.wikipedia.org/wiki/Acceptance_of_responsibility

[1] https://www.marketwatch.com/story/martin-shkrelis-lawyers-fa...