If its not just a matter of perspective and only medication can help, etc, then why do we call depression a "psychological" or "mental health" concern? Why isn't it just considered a neurological disease?

Not sure what your point is, many mental health concerns are caused by neurological diseases.

In case of depression in particular, it appears to be a label given to a big bag of various issues you may have causing similar symptoms.

Depression is increasingly starting to be seen as a neurobiological disorder as we learn more.

In my own opinion, we need to stop viewing "mental health" as a separate class of conditions from general/physical health. A mental illness is a health/medical condition just like any other and shifting our views and diagnostic criteria in that direction would do a lot to remove the stigma associated with mental illness.

Someone with depression has a chronic illness, not a temporary "it's just in your head" condition.