Don't mistake my disagreement for a misunderstanding.
I'll try to make it very simple for you.
If a business owner employs a person for 40 hours a week, that business owner is deriving value from that person. If that person were, as you say, providing "worthless unskilled labour", the business owner would not employ that person in the first place. The very act of employing the person implies that the owner derives value from the person. So your argument about a person having no skills is nonsense, because the person has to have some skills or they wouldn't be employed. It also doesn't matter if that person has never had a job before.
So far there is no argument. If you can think logically, you have to agree.
Because the owner derives value from the labour of his employee, and this employee is employed full time, the salary must be high enough for the employee to live a life of dignity. We can disagree about what a decent life should look like. I think a comfortable home, healthy food and the ability to save some money is the bare minimum that should be considered a life in dignity. If you think that's too much to ask for, that's between you and God. You do you. None of my business.
Also, we are not talking about socialism at all. The idea that a business owner should pay his employees properly doesn't come from a socialist perspective, it comes from a place of basic human decency. The fact that some people seem to have no problem exploiting other people makes the law a necessity. A law is not socialist. A law is there to protect the weak. You can believe in a world without government, but just as communism is a fairy tale, this kind of libertarianism is also a fairy tale. Nice idea, it won't work. There must always be a balance, in everything.