I will not defend this as this is tragic and this should never have happened.
But I will say, John Oliver had a great point yesterday. Cops have too many responsibilities. They are not and should not be responsible for dealing with problems such as mental health. They do not have the training required for this. We need to shift the budget away from policing and towards services that support the community and deal with issues like homelessness and mental health. When you're dealing with someone with a mental health issue, the person showing up to deal with the situation should not be equipped with a deadly weapon.
Cops absolutely should not be involved. They are not equipped to handle this, and anything that threatens their safety is likely to result in a tragedy. It does not excuse the cops behavior here, but we need a system where they are not involved whatsoever in this situation.