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 the action or process of regulating or being regulated
It's a gerund of regulate.Your misreading would allow that regulation(s) take away freedom but laws and Constitutional Amendments don't. And that's just gibberish.
But, if your assertion is that they're the same thing now, then that's cool too, I guess.
It's really, really hard to equivocate the 13th amendment to, say, the EPA rules overturned by Michigan v EPA, or any of the other thousands of regulations imposed last year.
The obvious rebuttal being that "laws" allow for the military draft, which is also slavery, or jury duty, which is an admittedly much milder form of the same thing, or the internment of the Japanese, or the infinite detention in Guantanamo, but since you probably already know that libertarians wouldn't be on board with slavery in the first place and are just positing up strawman after strawman, I think it's fair to assume that your arguments aren't being made in good faith, so I'll leave you to it.