"My point ia we offer far above min wage because of high demand but low supply of workers! So why should a job with high supply pay the same?!"

The entire concept of pay equity, rather than pay equality, is founded on the notion of "work of perceived equal value", which is a soft argument that is essentially malleable.  Who determines that work is of "equal value"?

Consider the primary argument that child care should be valued MUCH more highly than it is. The market says, "It's a job that requires little education, little skill, and that many adults get into simply by having a child, so there's a huge volume of labour that can do the work." Pay equity advocates, however, argue around the value of the work to society, and because raising the next generation of workers/taxpayers is important, it should get paid more. It's a fundamental disconnect from the realities of the market.