IT'S ALL ABOUT THE RIDICULOUSLY HIGH MINIMUM WAGE
Unemployment is a labor surplus. Shortages and surpluses are price phenomena, not supply phenomena. You could have a surplus of BMW's by pricing them at $100,000 each, you could have a shortage of same by pricing them at $10.
Back in my hometown area the Burger King is advertising for help wanted at $9/hr. Unemployment is ~2.7% in the region.
Wow ridiculously high minimum wage??? It's something like five and a half here in NY. Imagine what that is after taxes. It's not high at all.
If they paid Americans a decent wage, they'd do the work.