There is actually a very real concept that known penalties deters crime. If you stop any significant punishment, criminals are aware, emboldened, and crime increases. Milwaukee is recently reeling in thousands of reckless car thefts, and this is what the perps say themselves:

"I know people who have got 200 car thefts, 300 car thefts."

Interviewer: "Have you thought about how you would do that time?"

"Shit, you only get 3 weeks. It's a misdemeanor!"

Interviewer: "You only do 3 weeks for stealing a car?"

"Hell ya, it's a misdemeanor."

https://youtu.be/fbTrLyqL_nw?t=429