See it where? This anecdote sounds more like a jury or a judge making an exception in an extenuating circumstance, than the exercise of an existing law, or precedent.

How was this an exception? The attacker was charged, they chose to give a (very) lenient punishment with the circumstances considered.

https://www.rollingstone.com/culture/culture-news/charlottes...

It is an exception because it is not representative of most assault charges in the US. Getting charged for assault, and then a pat on the wrist, for punching a Nazi is by definition an exceptional event. Rolling Stone, a cultural icon, does not gamble advertiser money on boring, unexceptional events.

I thought that (beyond the death penalty) the jury does not get to determine sentencing, just guilt.

Depends on the Jurisdiction.

https://www.rollingstone.com/culture/culture-news/charlottes...

So killin' wasn't involved?