Not so sure about this article. I mean, "yay, sensitive guys unite!" - I'm one of them. But I feel like making your emotional affections a public display defeats the purpose. More of a public performance of shared feelings for likes and supportive comments. Which becomes more important to the teen? The likes and comments, or the status itself?
Social media is weeeeird.
What's more important, telling someone about your problem or hearing their support?
Socializing is weird- media and networks only change the ways in which it's weird. I think that the main point stands- this is a healthier social landscape than it was 20 years ago. As someone who grew up at the same time as social media, I think that's been the trajectory of my life as well.
On the other hand, I would agree with you that I wouldn't say that any of these positive social ramifications are making them better writers. I think that's stretching the term a bit. Sure, it's great if you're comfortable writing about what's dear to you. But you should also know a language and some composition.