Awful post. There's such a huge flaw in the argument that social insticts cannot be acquired at a later stage in life because that would mean that even normies fail. Yes, you act at instict at first. No, you won't act at instict forever. I believe social insticts such as what the person is describing here is something that you will subconciously pick up on unless you're unironically diagnosed with autism.
If you could not acquire social insticts, and have to rely on intuition then even normies who CAN socialize would never be able to: take a new class in school, join a new club, change school, move to a different town and biggest of all. Move to a new country.
People can move to new countries and fully acquire its cultural norms, social insticts and unwritten rules which is a huge flaw if what that poster said is true. You can start again at any point in life. You will struggle at first, then develop instict for it. Even we can do it.
Imagine a world in which you could never acquire new social insticts, or pick up on any new social cues (without genuinely having a diagnosis). You could not start posting on a different board, a different chan, a different part of the internet, hell even from general to general on the same board you would stick out like a sore thumb. It's simply something that animals pick up on.
I am saying this as a person who is very socially isolated, and have no social skills at all. I do not speak unless spoken to and I do not engage in any social activies by my own accord. Yet I know, that if I try you will eventually pick up on it. It's in the nature of our species.
If you have ever moved to a different board or chan and adopted its norms you should see the huge hole in the argument. Seriously, what a horrible post.