Why does the Moon look huge near the horizon?

Answer: Your brain compares it with trees and buildings

Earth's air acts like a giant magnifier — Not really. Atmospheric effects can distort the Moon, but they are not what makes it look dramatically bigger.

Your brain compares it with trees and buildings ✓ — Correct! This is the moon illusion. Near the horizon, your brain compares the Moon with familiar foreground objects, so it feels much larger than it really is.

The Moon is physically closer at moonrise — Nope. The Moon is not suddenly much closer at moonrise. The effect is mostly in your perception.