Just read the exception clause in the 13 amendment itself. All the proof you will ever need.
The amendment, which officially abolished slavery in the United States in 1865, includes a loophole regarding involuntary servitude.
www.history.com
It's there plain as day.
That's as specious an example of "slavery" as
those liberals who say it's slavery to have to
work for money. They call it "wage slavery".
But you missed the one real modern vestige
of slavery in violation of the 13th Amendment,
albeit one that's currently in abeyance (since
Nixon cancelled the draft in 1973).
Military conscription....
It is involuntary servitude, but not punishment
for a crime. It's a clear violation of the 13th, yet
government still requires cis (not trans) men to
register for the draft, with punishment for those
who don't. And is retains the power to implement
the draft if it wants.
It also runs afoul of the Equal Protection Clause
because it's highly discriminatory, exempting
clergy, women, & trans men.
I'd describe my personal draft resistance, but RF
rules prohibit it.