Indoctrination is an interesting word. Might be more concerned with parent and media influence in that realm ("media" includes social media).
Adolescents tend to consider the source, at least on a subconscious level, and value information differently. A lifelong influence of parents and family has the power of longevity and proximity. Social media has the power of being what adolescents choose to view and listen to. A high school teacher for 4-5 months in one class? Probably not going to cause some massive change in anyone.