I would suggest that the level of the article must be 4 looking back at 3, because the author is making the argument that once you get to the point of maturity where you are choosing your own social networks, you may gain the perspective to recognize their very important role in your self-authoring task.
That said, I would also note that the 6 different networks listed are all likely to be formed by the time a human has achieved the age of 30. So, by the time you are on your first grandchild, second divorce, 3rd career, 4th midlife crisis, fifth house... MMV.
I am reading "The Way Home" by Mark Boyle and he writes:
My life is my life, and it's prone to the same contradiction, complexity, compromise, confusion and conflict as the next person's. My ideals are often one step ahead of my ability to fully embody them, and that is no bad thing; in fact, as we will see later on, I wonder if hypocrisy might be the highest ideal of all.
I believe this might be a Level 4 towards Level 5 sort of thought. As applied to social networks, it might be described as the ability to hold the perspective that your self-authored choice of social network does not preclude the existence/value of other social networks. For instance, in Boyle's case, his ability to simultaneously hold the ideology of veganism/animal rights which he subscribed to in his late 20s with his current rural, low technology reality in which he finds himself feeling vital while drinking fresh animal blood.