Mostly because of an outdated view on justice and crime.
Whereas in Sweden for example, a violent rapist was awarded ~$84k - https://www.gp.se/ledare/v%C3%A5ldt%C3%A4ktsmannens-skadest%... - after he turned out to be a minor but had been tried as an adult, and in the end spent less than 2 years in prison.
Some of ThePirateBay founders had longer sentences, absolute clown world.
There might be an argument if the US actually had lower crime or recidivism rates than European countries, but it does not have that.
Yes, it takes some effort to overcome that primal view on justice, but it leads to a more humane society with less crime.
That injustice is separate and distinct from the one he committed on a fellow human being, and for that case he spent two years in prison. This sounds unreasonably short, but without further information, who are we to say whether that was acceptable or not? Perhaps two years was enough to help the rapist overcome his violent tendencies.
Mostly because certain people profit off it. If you have private prisons and lifetime voting bans for someone locked up for a few months you have mega incentives to get a lot of people behind bars.