I don't think libertarians really see wage slavery as the worst thing.

I think the fundamental difference is that libertarians don't care about outcomes. Or, at least they don't think that they do as long as they have food in their stomach and a barrier against the cold.

In their minds, it's all about them not being compelled to partake in anything they don't want to. If that means starving, fine (so they say, and I'm very suspicious of this claim), but at least there was no authority over them.

Most sane people strike a balance between valuing good practical outcomes, and more abstract notions like liberty and justice.

Full authoritarians say that only outcomes are important, that abstract notions like freedom are impediments to the greatest good, and you end up with things like the USSR.

So you're right that there wouldn't be a minimum wage... But you're wrong to appeal to the concept of wage slavery because it presupposes a libertarian values satisfactory outcomes. They don't.

Honestly there is no talking down a libertarian without first convincing them their lives are worth more than some definition of liberty.