"Their susceptibilities are natural, but are not necessarily always to be deferred to."

Firstly it is clearly incorrect to call the UK by the name England. Why excuse incorrect usage of terms rather than defer to the correct usage? For instance would all Americans be happy to be called Californians just because California is the most populous state? Secondly if you know that using this incorrect usage is likely to irritate or even offend then the usage of the incorrect term moves from the ignorant to the arrogant. Would a Texan be happy if I said "I don't care if you don't like being called a Californian it's what I'm calling you so you'll just have to accept it"?

If an American came into a local pub here and called the punters Englishmen then they are likely to be laughed at and maybe gently teased for their ignorance. If however they went in arrogantly announcing that no matter how the locals define themselves (ie as Scottish or British or Scottiah and British) they are in the visitors eyes English then the reaction is likely to be a tad hostile.

Isn't it easier and more polite and respectful just to use the proper terms? Say Scotland when Scotland is meant; England when England is meant; and Britain when etc etc etc