The US military, especially, is the largest job and training program anywhere in the world, including the military industrial complex (most of those military contracts, incidentally, do not just come with jobs, but with demands that those companies hire x0000 (3 or 4 zeros) in the states that have the highest poverty levels).
I'm not saying it's an ideal occupation (although, hey, Keynes seemed to like it when he was less on guard). So yes, I'd also much prefer them to be building better infrastructure. Or perhaps have a much cheaper postal service.
> That's where you money is going to, not $6 an hour fruit pickers spending all their money in food.
Perhaps. But the inability of the working poor to pick fruit at $15 an hour IS due to (mostly illegal) fruit pickers.
Then, if fruit pickers made $20 an hour, you would be getting all of your fruit from Mexico/Central America, and fruit and all products made from it would be more expensive.
Other jobs like gardening and landscaping would simply either not be done, or get done by property owners themselves. Now they will be tired, be less productive at work and have less time for their kids, or, see their property value drop while their local crime rate goes up.
It would be very bad to kill it without replacement.