This is trying to ride a thin line and I don’t think it hits the mark. Sure, there are skills involved in any labor. But “unskilled” is just shorthand for not having particular requirements that are rare enough that labor gets to charge more for them. It’s not a myth that there are jobs where a large enough group of people can do the job and it pulls down the price you can charge for your labor when you are doing the job.

If anything this is an argument for a higher minimum wage, not a union.