Opinion pieces are fine, as long as they explicitly state the status of the premise that they start from. In this case, the premise he starts from is "most users of social internet sites are not teenagers." Then the opinion part of the piece tries to explain why that is.
My complaint is that there's no evidence for his premise. In other words, he's trying to explain something that might not be true in the first place. I worry that he, and his readers, don't know the distinction.
My complaint is that there's no evidence for his premise. In other words, he's trying to explain something that might not be true in the first place. I worry that he, and his readers, don't know the distinction.