Dumb ass missed.

I don't know- getting the ear is pretty much being a millimeter from dead on. No pun intended.

A 20 year old White male with an AR style gun? He wasn't aiming at Trump, he was aiming at the non-Whites around him. Trump just got lucky.

130 meters, no prior military training, opportunity for few shots, most of them almost hit him, one grazed the ear. Dude had potential, Trump was lucky.

Something as mundane as a sudden gust of wind, or a slight scope miscalibration, could have made the difference.