It really isn't that at all, he argues that it's wrong to discriminate but that government interference in the freedom to make contracts isn't the best solution. He goes on to elaborate an make a case for how else it might be better addressed. The article intentionally misleads by clipping the quote out of context.
But it is.
This the the same argument against minimum wage. It's just wrong.
The government should absolutely set a floor on wages and discrimination.
There must be a standard to minimize friction. It's just not something that anyone can do by themselves.
Discrimination was the actually historical basis for the US introducing a minimum wage. There’s available testimony from congress that show that the intention was to push women, blacks, and immigrants out of the workforce.
I think it is totally within the bounds of reasonable discourse to discuss if minimum wage laws achieve their stated goals.