I think the example is backwards, because the 13th amendment restricted the government, not the people.
Section 1. Neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction.
Section 2. Congress shall have power to enforce this article by appropriate legislation.
Clearly gives the government power to ban slavery. It does not enshrine any rights in citizens, and indeed notes that involuntary servitude may still be imposed as criminal sanction.
Its not banning the practice of slavery but the promise of legally enforcing them.