> the rules of society are designed by the neurotypical majority
That's another way of putting it. I'm not sure the majority are neurotypical however.
I think, rather, "neurotypicality" is a background assumption of certain institutions because it's easier to design for an average even if it doesn't exist (no 1 human being is mean in every respect).
However those who experience life-long mental health, and esp. for most of their childhood, I think are overwhelmingly "conservative" in their personalities. And I think these sort do tend to find themselves in more elite/visible positions.
Political systems represent those who hold power. They do not represent a majority (power is the mechanism of representation, not mere existence).
In democracies, there is more "tending towards the majority". But still, it is very much a symptom of who can be elected, who is elected, etc.