There's a place for stoicism, and it can be a great trait to have, but the emphasis on it above all else, the numerous biological, environmental and societal factors that contribute to severe mental health, can become counterproductive.
If someone with major depression and suicidality is implicitly told they arent stoic enough, it can perpetuate the mental health problems. This is where the poster is correct. Social support, counselling, support putting a roof over their head, medication etc. may be more helpful for that individual.
Another point is that people might need assistance in changing ingrained perceptions of the world to become more stoic. This can only happen when mental health is destigmatised so they feel like they can ask for help.