One of the insights of MacIntyre as I understand it is that the good life does not consist in the realization by the individual of abstract virtues. Rather the virtues are realized in members of a community through the concrete actions and life within the community. Virtues are more or less encouraged in various ways in the community but not as abstract concept, rather as lived actions.
Consider something like a professional society. The society encourages the excellence in each of its members through various means, such as continuing education, professional standards, codes of conduct, etc. The political society does this for the comprehensive human excellence, i.e. the good of the human as human and not just as blacksmith or professional.
With this in mind, the criticisms frequented upon Facebook seem to have a real basis. People may say that Facebook is a positive good because whatever and you can be virtuous on Facebook, etc. The criticism is that Facebook encourages narcissism, etc. The particulars do not concern me.
While considered absolutely, Facebook is a good in so far as it is a certain perfection of the practical intellect as any invention or technology is. However, considered with respect to the environment it encourages, it may be seen as contrary to the human good. The nature of social media in itself seems to encourage vice such as pride, arrogance, vanity, etc. Even as I blog I see this in my act of writing. Something like Facebook seeks to encourage these vices by encouraging sharing as if everything you say or do or picture or text is of great importance.
Again abstracting from particulars, it does seem that something like MacIntyre’s analysis could be applied to such concrete actions encourage by Facebook, Twitter, Twitch, YouTube, etc. Not that they cannot be used for good by virtuous people, but rather they encourage a concrete way of life that is contrary to the human good.