[gliese1337]

    The OP didn't even say they were American

Doesn't matter. The same argument applies regardless of where you live.

    the choice isn't between current facial expressive norms and different ones, it's limiting the ability of children to read the most expressive part of our faces entirely.

So what if it is? I see no evidence that that is actually a problem. It is only a problem if you assume that we must maintain current social norms; otherwise, you can just update social norms to not depend on error-prone interpretation of faces in public. Congenitally blind people develop just fine without ever seeing any faces at all--and nobody is saying you have to stay masked 24/7 in the privacy of our own home, so it's not like seeing children are deprived of any and all facial stimulation anyway.