Americans are generally sentenced to prison for committing specific crimes. Sure there may be some things you think the law should decriminalize (do vote), and also, sometimes innocents are imprisoned, which absolutely should not happen. But our prison system as a whole is not comparable to the indefinite detainment and reeducation of people purely due to their ethnicity or religion, which is happening with Uighurs.
A better comparison would be Japanese internment camps - I don't think anyone is defending those anymore.
You say "committing specific crimes" like popular support for the war on drugs wasn't fueled by racist propaganda. You say "sometimes innocents are imprisoned" as if overburdened public defenders don't recommend a guilty plea because it's "safer" than attempting to establish innocence in a racist judicial system, biased again certain races in arrests, extrajudicial killing, in prosecution, in sentencing, in the jury supposedly of peers. Indigenous women are still being sterilized against their will, a continuation of centuries of genocide.
No, it's not a perfect comparison, in large part because responsibility doesn't rest on a single central entity. But it's awfully similar. The US has more prisoners per capita than any country in the world. The "scale" of it is atrocious (as is the Chinese treatment of Uyghurs, just to be clear) and America's lack of moral standing on this issue is a big deal because until recently, we've been both a military superpower and the vanguard for human rights.
