I can't see that there's anything racist about saying that certain peoples/races/nations behave in certain ways, even if those ways are ways that certain other peoples/races/nations might, other things being equal, consider rude. Not least because as often as not, other things are not equal.
The door-holding is a good example. It's been suggested that Poles walk through doors and don't hold them for anyone following. This suggestion has been interpreted as effectively saying 'Poles are rude'. And, further, as racist. I find this baffling.
My sister told me that when she first went to live in Denmark, she was surprised to find that people entering, say, a department store, will not - as most Brits would - glance back and, if necessary, hold the door for someone following. They just walk through and let go, and that's that. She never for a moment suggested - or felt - that that meant Danes were rude. Just that they do that particular thing in a different way to the way we do it. And once you get used to it, she said, it's not a problem. You just take on board the fact that people won't hold doors for you, and behave accordingly yourself.
I really can't see anything racist in that. Or even rude.