The US has a culture of retribution [1] against convicts. This has led to the election of many politicians, prosecutors, and the like who campaign on a "tough on crime" platform [2]. In spite of what the wikipedia article on retributive justice says, I believe schadenfreude is a component of this. People see stories in the news about violent crimes and they often gather outside courtrooms to cheer when harsh sentences are handed down, including the death penalty.

[1] https://en.wikipedia.org/wiki/Retributive_justice

[2] https://en.wikipedia.org/wiki/Joe_Arpaio