This video doesn’t prove that Carnell Snell was holding a gun when he was perforated by the police. It proves that he had a gun. Which is entirely relevant, if not decisive.
But what’s up with Mexican carry? I mean, the same advantages of holstering your firearm apply to good guys and bad: retention, presentation, and safety. And yet I’ve seen plenty of footage of criminals with guns stuffed in their waistband. Holsters aren’t that expensive. So why don’t they use them?