A knife wielded as a weapon within 20ft of you is very definitely a lethal threat. I don't know the circumstances of this particular situation very well, but if I shot someone coming at me with a knife and an intent to harm I'd be well justified in doing so.

You aren’t a cop. I’m 100% in agreement that if a citizen gets attacked by a knife wielder, the use of lethal force in defense is fine. However cops are professional peace keepers. They have training, equipment and numbers on their side. You can watch videos of European cops dealing with a knife threat, it’s really not hard.

Circumstances matter, but it can be done (eg https://www.youtube.com/watch?v=9mzPj_IaMzY made the news a while ago).

Here in Germany, people wielding knives get killed from time to time as well. Pepper spray tends to get used first, and I do not remember any case where a dozen rounds were fired[1] (German police fire on the order of 50 rounds total per year, cf https://de.wikipedia.org/wiki/Waffengebrauch_der_Polizei_in_... ).

[1] edit: apparently, this does happen, cf https://de.wikipedia.org/wiki/Tennessee_Eisenberg

A police officer i knew, in Europe, had practiced self defence and disarmed the knife person, no one hurt.

I would have wanted a tazer, personally, if i was a cop.

Never having been in a knife fight, I'm not going to speculate or second guess people who put their lives on the line. What's your expertise in this area?

No expertise, but just offhand one could use beanbags, rubber bullets, tear gas, pepper spray, tranquilizers, etc - Is there a good reason that these are not options? Why jump straight to shooting someone multiple times? Maybe I’m just not understanding something.

I don't know how effective any of those are at stopping someone who intends to hurt you, but Tasers, which were specifically discussed because the officers weren't carrying any and some people thought they might have helped, apparently are only between 50% to 75% effective.[1] That's a big risk when someone is only a few steps away.

1: https://www.npr.org/2019/06/27/729922975/despite-widespread-...

That is only with the shooty prongs. Get right in there and a taser works 100% of the time. Hit 'em in the spine and the legs drop out. The problem is cops are too concerned about their own safety. They are cowards, and when they get scared they shoot.

This is oversimplification, and is unhelpful.

Public and local priorities determine budgets. Departmental budgets and priorities determine what equipment is purchased and equipped, and the degree to which their usage is trained. Training and official departmental policy determine the degree to which de-escalation is a priority, and whether the officers are obligated to follow an escalation policy in which tools they employ, or if they're permitted a toolkit approach.

... and all of these things differ per locality.