You could say that they took decades or centuries to develop, sure, but nobody has centuries worth of ‘feed’ in their head. I’m 43. I can have no more than 43 years in which to build my own indoctrination set. And there’s a primacy / recency effect going on there too, from psychology.
Indoctrinations that affect your behavior are most likely to be ones you picked up as a kid, or ones you picked up in the last few years. And those are the bounds around which the progressive / traditionalist struggle manifest. Went into a little bit of that here, towards the end:
If I were spitballing, I’d say that everyone’s behavior is probably about 50% genetic, and 50% learned responses split within the first ten and last ten years of life. We’re 15 years past the founding of Facebook at this point, so I think our collective indoctrinated behaviors are probably around 50% a result of the feed, which would make up about 25% of everything we think and do.