Let me address a few things. First, I didn't post my response because I think the incarceration rate in the U. S. is OK. It's not. Incarceration of non-violent criminals is especially aggregeous. Private for profit prisons are a horrible idea.
I responded because the OP posted an image comparing the incarceration rates of the CCP's cultural revolution to the current U.S. incarceratiom rate. The implication is that because the per-capita incarceration rate was lower in China during that time, it was a nicer place to live than current-day America. That ignores the part where the Chinese government starved to death 15,000,000 - 55,000,000 people, or put in Americanized terms: somewhere between the entire population of Pennsylvania to the entire populations of California AND Pennsylvania.
Claiming that a per-capita measurement normalizes all factors, makes a sampling error based on survivorship bias. It is highly unlikely that the overlap of people who starved to death during the CCP's famine had the same incarceration rate of those who did not. I'm guessing rich and party aligned individuals had a much lower rate of both starvation and incarceration.
This would certainly be true in the U.S; Incarceration rates are much higher for low-income individuals: https://www.prisonpolicy.org/reports/income.html. Low income individuals are also more likely to starve to death in a famine* (*citation needed). Now imagine if the United States government starved to death the poorest 10,000,000 people in the U.S. and then started bragging about how much it's per-capita incarceration rates have improved!