The next time someone tells you a sniper could reliably hit an ear with any weapon at any range ask them how they'd control for ballistic variance of the ammunition...
Don't go in for conspiracy theories. They fall apart at the mildest push.
Even match-grade ammunition can have 3-5% energy variance, round-to-round.
Trained snipers are aware of this. It's not the movies. No one takes that shot.
Occam's Razor. Kid who was part of Trump's violent cult took umbrage. Perimeter security was lax.