One: man people really need to read and assimilate the bipolar element and stop simply calling the assailant an idiot or stupid. That is actually idiotic, uninformed and stupid behaviour. If you don't understand the condition don't comment specific to his behaviour until you educate yourself.
Two: tragic situation all round. Understand the response (relative to US) and it's tragic it cost someone with a condition that can cause such behaviour to loose their life and its also obviously extremely distressing for the victim and his family.
Three: while this will inevitably have impact on the current situation it'll mainly be those taking this (deliberately or otherwise) out of context. It's also alarming that the current heated situation in US (which is genuine and understandable IMHO) is likely going to see more incidents on both sides unless a way is found to stop things continuing to escalate. Hopefully at minimum the true aspect of the assailants unfortunate condition will be properly taken into account and understood to have caused a singular response vs the dumb assumption lots of BLM supporters are suddenly going to be acting in a similar manner.
Four: while specific to US I understand the action of the victim there's no doubt in my mind from perspective of someone outside the US this could have been handled better if no lethal weapons were involved. Living in UK I'd expect the guy to be restrained while alive and am confident he would most have likely have been. Obviously though if you were armed and in the victims situation resorting to lethal force is understandable if regrettable. But for sure other options than verbal commands to shooting are available.
Five: the shooting element speaks to the basic issue of gun ownership: it gives a sense of individual security but the trade off is increased fear an assailant is armed and higher statistics of shooting that similar Western countries. In short if you actually want to reduce the incidents of shooting you have to surrender having weapons for your own protection and put more faith in unarmed/armed police according to circumstance and the resultant probability that strong gun controls mean the assailant most likely won't be armed with a gun themselves. The statistics show it's unlikely you can have both at the same time IMO.
Bottom line it's a tragic incident and one of what feels like a growing number of incidents growing out of the current situation of unrest and concern.