A recommendation from a person you know takes into account not just their knowledge of your preferences, but also how much and in what way they like/care about you, and conversely, your taking of the recommendation is colored by your rapport with the recommender. All that is something a recommender system has no access to.

Or, more bluntly: you aren't going to mate with a For You page, so it doesn't have the same evolutionary cheat code to your preferences as other people have.