wages are decided by employers, not by employees. I really can't see what's so hard to understand about that

Might you be able to see a difference if an employer was looking to employ several persons (possibly for temporary work) and had the chance to choose between two groups of applicants, both capable of doing the work, where one group wanted to be paid the legal minimum wage, but the other group wanted to be paid minimum wage plus 10%?
Most employers would think the minimum wage was the better offer.
So it is the employees (ready to work for a lower figure) who are driving the wages down. "What's so hard to understand about that"?