40-44psi... that's how much the guy set my new 20s at. Is that entirely too much? I know recommended is 32-35psi. Max on the tires is 44r/50f.

Think he did it because it's lower profile? Because they're new? Any other reasons?

That sounds high to me. I know you can inflae the tire to the high 30's if you are carrying 4-5 people and cargo or towing something, but that sounds high for typical everyday driving.