I've heard this before, but at the same time, when I've been to the UK or Spain, it didn't seem to be necessarily the case.
My understanding is that it's socially acceptable to wear revealing clothes in the same cases it is here in the states but at the same time, a lot of settings where revealing clothes would be the go to in the US have a more modest alternative (eg in Spain one could wear a bikini top with shorts but also could wear a flowy maxi dress), but I am unsure what the reality is.