Honestly, I think part of it is that having an entire community of people suffering depressive symptoms becomes a depressing environment.

I'm sure I heard this in a Brene Brown video, but in order to be able to help someone else, you need to be in the right place yourself. Two empty glasses can't help fill each other. And most people can't help an entire community of struggling people, one glass can't help fill fifty, it's futile and self damaging to try. It's why we have professionals that do one on one therapy.

And, this might be unpopular, but I think historically this is why we have priests too. I'm not religious, but I think that community offers that to some people.

Sometimes people need to vent, and some people aren't lucky enough to be in a position where they can vent to anybody, but I don't know if diving into a community where you expose yourself to everyone else's problems too is the solution. Things like addictions counseling are controlled, with professionals at the helm, and often in small spaces, with a prescribed meeting time and an end.