I wonder if this reply isn't coloured by the stigma GP was trying to point out. Recklessness and paranoia aren't in themselves mental illnesses. What portion of the general population experience paranoia or recklessness vs people with mental illness? I bet the rates aren't all that different, it's just that in extreme combination it earns the person a de facto badge of "mentally ill". That's usually shorthand for "I don't have enough information to understand this persons motives, so I'll label them as crazy and be done with it".

> I fail to see how suggesting that this shooter is mentally ill would contribute to the shooting and killing of mentally ill patients

It's possibly perpetuating the widespread belief that people with mental illness are predominantly violent. The _vast_ majority are not.

> This shooter is not being stigmatised at all, as i see it: attention is being drawn to a potential sufferer who is not receiving (adequate) care.

I guess the "mentally ill" label is a bit more compassionate than "violent criminal", but it also applies to millions of harmless people who don't necessarily benefit from being lumped into the same label.