Would you feel comfortable to fly (both as crew or pax) with a pilot who has a mental history? In truth it's quite a dilemma for the airline.
I'd far prefer to fly with someone who has acknowledged their mental health issues and believes themselves, with the agreement of mental health professionals, to be in control of their mental state than with someone who has unacknowledged and/or unmanaged problems, especially if they are problems that are actively being hidden.
Given the prevalence of mental health issues in the general population, it is not unlikely that there are at least some pilots that should not be flying. This means it is very important to provide the greatest possible support to those who put their hands up and ask for help so that others feel encouraged to do so. This is not about judging people, it is about achieving the best outcomes.