The thing is it's not that these are just cool cognitions. There are values bound up in them, that's what makes them effective as norms. People invest themselves into, and shape themselves through, normed practices and ideals. Beyond that, they have to justify themselves to themselves. This means that outliers aren't just perceived heuristic 'blips', but as potentially dangerous inasmuch as they can destabilize those values, and a person's sense of self. So outliers are mocked, derided, or in the least case, patronized, if they're seen as otherwise conforming to norms.
As far as coping with it, really I think the best thing is to spend time with other outliers, in order to validate your own choices and just spend more time feeling comfortable. Much easier, then to be tolerant of judging others, or take on the goal of educating them if you want to.
e.g. if not having children is an issue, spend time with other child-free couples. there's even a national organization for that, i think, child-free something, sorry can't think of it.
all of this will be harder outside of metropolitan centres.