Who had much more firepower? That the cops knew about? The shooter was accused of ambushing the cops, but didn't fire until the cop drew on and aimed at a retreating protester (that part wasn't in dispute, it was part of the cop's testimony). AFAIK none of the other protesters had firearms, just the single shooter hiding on the edge of the woods.

This was shortly before two people got murdered on camera by cops in Minneapolis, and after/around the same time as several other attempted murders (that would have been successfully spun as something chargeable on the victim, if not for video evidence showing plainly that the cops were lying)... so... it doesn't seem like a totally crazy notion to me, that a person might have shown up armed intending only to fire if it looked like a cop was going to shoot someone without a great reason. Maybe a jury would still have convicted (there was a bunch of fuckery with jury selection on this case, incidentally, and I mean way more than usual, even, it's worth reading about; like after what the court selected for on the jury, I believe they almost certainly would still have convicted) but not even being able to raise that defense seems nuts.