You have a degree in economics and can't answer these questions yourself?
What do you
think the answers are?
Saying that economics is a too for the rich and powerful sounds pretty silly to me. Economics is merely the study of how the economy works. Anyone who wants to understand how the economy works can use it and benefit from the knowledge (and presumably get a job in a related field).
Policies like a higher minimum wage are problematic due to the secondary effects. As you know, the labor market is a real market, and supply and demand applies. So if the price of labor increases, the demand will decrease - unemployment will increase. How much....well, that's what economists are for. But such policies are also understandably politicised.