[Tzimisce]

If the Constitution doesn’t apply to state or local governments, there would still be slavery.

[Edward.Fish]

If the Constitution doesn’t apply to state or local governments, there would still be slavery.

I didn't say Constitution, I said First Amendment, which is what he's likely citing.
(I hate Free Speech Zones very, very much; but I also think we ought to treat the Constitution as if it were the Supreme Law of the Land, and that means paying attention to what it actually says, not what nine black-robed guys say that it says.)

[PAR35]

If the Constitution doesn’t apply to state or local governments, there would still be slavery.

You probably should get a copy of the Constitution, and read it. It still allows slave labor, it just restricts it. Notice that the sixth word of the 13th Amendment is "EXCEPT".