From what I gather, this is another case of road rage that went bad and ended up stupid.
I am going to say something that will be unpopular with the Victimization crowd and those Bleeding Hearts and La Raza types: Turcio had it coming since he was suffering a bout of Machismo.
At 2:36, Turcio says he was driving all peacefully, and the other driver flipped him the middle finger (“el me venia sacando el dedo!”). The at 2:54 is where I reckon Turcio sealed his fate with his mindset “Aqui mandamos nosotros!” (We are in charge here!).
Also revealing is what the wife said right after that, something along “mira lo que hiciste” (See what you did?) and when he rejects it, she loses her mind and starts screaming at him. He argues back and ends up hitting the truck. He was then primed to do something stupid and eventually it came to be. The taser dose should have been a warning to Turcio that the cops were done playing games. but I believe his machismo shouted at him “You have a knife! You can take them all Daniel!” and he believed it.
The family is already seeking some monetary compensation claiming the usual “He did not need to be killed, he was murdered by the cops, blah blah.”
Nobody’s fault but his own.