Are US police too quick to shoot knife-wielding suspects?

Yeah, that video wasn't even close to "quick".

Also, reading further, this jackhole apparently was (or at least may have been) the person that called 911 to report a drunk person with a gun, and gave his own description to the cops. So fully suicide by cop. Has an object in his hand, advances multiple times on police, acting in a belligerent manner. And people are still wondering why he was shot? Hell, it was even only just one clean shot. Not like they unloaded several clips into him.

No, I have been in this situation a couple of times in 20 years as a cop and hopefully I never will again. Having tasers now helps give another tool, but as often as they fail, the rule is you have lethal force first, and if there are multiple officers you can try less lethal options. I go to work hoping to never even have to pull my duty weapon, much less truly use it. But sometimes we are forced into it.

The 21 foot rule the article spoke of is something all LE is trained on. There have been many studies, and I have tested it myself, that a person with a knife can close 21 feet and stab you before you can draw and fire. And we do drills where you can fire and put 2 rounds on target in 1 second. Of course that distance is less if you are already on target. But most of these guys are wanting suicide by cop or they simply drop the knife when first encountered. I don't want to have to shot someone, and I understand there are inherent risks in the job, but I'm not going to risk my life unnecessarily.

I have been on scene where a guy had a Rambo style knife and wanted suicide by cop. One officer holstered his weapons and tried to talk the guy down, but we still had to shoot him cause he was having no part of it. Once he came at us and was within 7 feet, there was no choice. While we (cops) have had tons of training dealing with mentally ill or emotionally disturbed people, we are not psychologist or mental health professionals. Our function is to enforce laws and protect the public. Most agencies don't have enough resources to back off, clear streets and spend 45 minutes trying to calm a mentally ill person with a knife. And that person is definitely a danger to the community if we don't deal with them. It's unfortunate to have to take a persons life in these situations, and it's something you second guess yourself on and have to live with for pretty much ever. But we have an obligation to act.