I’m currently reading a book about the history of the British Empire and I think this temperament is older. When Australian and Kiwi troops were called to support Britain in the first World War, they were baffled by how much shit the Brits were ok with taking from their superiors, while the Brits were surprised how undisciplined and prone to protest their Australian and Kiwi counterparts were. You can look even earlier. While France at the end of the XVIIIth century had a bloody revolution, which did make some people in Britain think about their lot in life, they ended up mostly just talking things over, making some mild reforms and that’s it.

So I don’t think it’s blitz. It’s an older trait of avoiding internal confrontation (which doesn’t seem to extend to the Irish who on a number of occasions throughout British history decided to either leave Britain for greener pastures, or were more willing to be a bit more aggressive).