> a) prevents people who are happy to work for less obtain a job which is uneconomical at the minimum wage, or

Can you convince me this argument isn't also in support of slavery? (through fear)

Or was that actually the point and you mean to advocate for slavery?

Your arguments for b are equally malignant. If you will pay someone the minimum mage, for a minimum amount of work, and everyone else who could perform a higher standard doesn't because you refuse to pay them more than the minimum wage, good! Providing equal value of effort for value of compensation isn't communism, that's known as capitalism.