There's no healthy social media. Please focus your resources on Firefox.
I am a bit more optimistic than that. Social media depends on how we use them, but because technology is advancing so fast, a lot of people have yet to settle on a usage pattern that is healthy for them.
But I do agree on Mozilla should focus more on Firefox.
But the whole point is moot anyways. As long as SM is designed to drive engagement by exploiting the most base instincts in us, we will keep seeing unhealthy behaviour.
Until number of emotionally unhealthy people is <<<< mature healthy people, with time, SM will always be unhealthy.