One way roads and split highways exist, but even on any typical divided road, you obviously can still drive the wrong way. Either way, you're conpletely missing the point. That phrase is used as a way of saying that if literally everyone else disagrees with you, then it's a lot more likely that you're the one who is wrong.
In this case, autism really doesn't have an "opposite". neurodevelopment is incredibly complex, and while some aspect exist on a spectrum, others don't. (and the traits or development patterns that do exist on a spectrum in this case exist mostly between autistic and allistic traits, not between autism and some "opposite" pattern.
And the other traits you mentioned exist on their own orthoganal axes.
What is that 'open secret'?