It might be a rule of the grammar that “Slavery” can not be put into a contract within a “voluntary system” (as it may not be possible in certain leftist systems). It’s outside the rule set, as “murder”: whatever that may mean is automatically illegal in any system.
Either way, that isn’t what is interesting, as those are empty sets:
what is interesting is the imperative to act, and phenomenon of action and it’s consequence.
Not too sure I get/ agree with most of the arguments going on other than that.
That said this will hopefully be my last words ever wasted on that man who I refuse to name