[Jtsummers]

I think the author would agree with you. She doesn't call Facebook the cause of her depression, she just found connections between it (well, social media) and her depression, and that removing herself from them alleviated her symptoms. In speaking to her therapist and other professionals, and other sufferers of depression, she continued to find this common theme: Social media made their conditions worse, or at least made recovery more difficult.

This isn't Facebook's problem, as someone else pointed out: 75% of Facebook users are almost certainly not suffering from depression. But it is a problem, and she wrote about her condition (as someone who's written about his own issues with depression, this is not easy to do) to present it to others, for them to maybe see a way to get a little better or perhaps to be more aware of what the condition is like for those that have it.