We may, but do you really think we have the most violent people in the world? Do you think we have 7x more violent people per capita compared to #2 China?
and...83 times the amount of assaults per capita (??) <page 2 on chart>.
It also says the US has 30% more people incarcerated than China which at ~4 times the population is indeed ~7 times the per capita incarceration rate. But given the stats above (along with our massive drug use and propensity to lock people up for that) it's not entirely unbelievable either.
I don't think the US has the most violent people in the world, no. But I do suspect the US has the most violent people among the subset of countries with the resources and framework to prosecute and pay for incarceration for that many people.
I scrolled year to year on that chart, and there are a lot of gaps, and all the years I looked at only had a few data points. I went back to 1988 and couldn't find the assault stats that showed up in the summary.
I suspect it would be difficult to find an actual breakdown of crime stats in China. It would be useful to compare it with a country that is more transparent with that sort of information.
Here's a blurb from the site:
The actual crime rate in China has so far been difficult to assess and confirm. Official statistics from the Chinese government says that crime in China is significantly lower than that of more advanced nations, including and especially the United States. Official estimates say that murder rate in China, for instance, is 5 times lower than that of the US.
#3 is Russia, which I would guess to be equally difficult to get statistics on.
Also, looking at the US crime stats, they are spotty as well. The assault rate you noted is from 1999, near our peak. Even with that we aren't #1 on almost all of the compared countries.
But some of your conclusions are right. The US incarcerates a lot for drug use, and incarcerates a lot longer for any crime. Furthermore, it's difficult to lead a normal life in the US with a record of incarceration which leads to more incarceration.
That just doesn't add up.