Obviously your software should present dates in a locale-aware manner, just as it should (where possible) present localised text. But if it's anti-American signalling to expect reference documentation and technical features for non-localised systems (such as the Go programming language) to use the internationally accepted standards for the presentation of non-localised data, then… sure, I guess I'm happy to signal anti-American?

But I am one of Those People who goes around $WORK's internal wiki (which has users in the USA and GB) telling people off for failing to use 8601 in their meeting minutes, so perhaps take with a pinch of salt.