As someone who doesn't care enough about this to do much more research than trying to slog through this shit-show of a thread, I'll just say three points.
1. If you're getting orders from a cop and you don't comply, you're asking for some sort of trouble.
2. If you're a cop and you decide that "some sort of trouble" involving non-compliance should be you gunning the dude down AND there isn't a factor along the lines of "dude was charging me with a weapon and ill intent", you probably shouldn't be wearing that uniform.
3. While I'm still not sure if dude had a knife or had something else (like a phone, which I think I saw mentioned here a few times), I think in light of recent events, especially in an area where body cams aren't a thing, a person would have to be a bit naive to think that the concept of a cop yelling "drop that weapon" when not sure if the guy is even holding a weapon, but does know he's being resistant, is outside the realm of possibility. All they need is plausible deniability in case shit does hit the fan -- such as "it's night, he wasn't complying and he might have been reaching for something". There's a reason why people are still yelling about Breonna Taylor in Louisville -- the simple truth that the police are hiding behind loopholes to keep things as close to "accidents happen; can't put the toothpaste back in the tube" where a person or two might lose their job, but aren't getting any sort of charges against them.