I work with potential violent mentally ill guys. The #1 thing that gets a lot of people hurt or killed is that they don't defend themselves from a violent attack coming from a mentally ill person whether its because of the social stigma or they think that the person is incapable of premeditated violence. Also as someone who has seen many mentally ill guys have to get taken into to custody by the police, they will fuck up a police officer in a second. A lot of them know the law and how society sees their disabilities, they will straight up tell you that they are going to hurt you (and then try to do it) because they jails won't hold them and/or you'll get fired/go to jail if you defend yourself (not true). So everytime I see a story that paints police in a bad light because they had to apprehend a person with a mental disability I take it with a grain of salt.
The accounts from the police and the witnesses aren't too different if you remove the sensationalism. The clear difference between the two comes down to what the man was doing when he got shot, which could merely because of different POVs/attachments to the suspect. Police are on edge with these types of calls because they walking into a pretty much verified dangerous situation, usually they roll up at in the middle or the aftermath of an altercation. And you don't normally call up the police over just any altercation with a mentally disabled person because the police won't do anything (even if they hit you first) unless there is a strong chance that another altercation will happen after the police leave. They tell person to just take their meds and stay in their room for the night.
All I am saying is don't jump to conclusions, the article is pretty sensationalized.