[grey-area]

You should be aware that exactly the same sort of banter is directed by English people at Welsh, Scots, French, Americans and practically every other nation living in England (I've experienced some of this myself as a Scot living in England), it is exactly the same in tone and intent as ribbing of English people in Scotland, and yes, sometimes it does have a nasty edge to it in any country, esp. when it is directed in a general way at an entire nation/race.

Silly, and sometimes ignorant, but there we are, that's patriotism for you; the last refuge of the scoundrel, as an erudite Englishman once said - you should hear what he had to say about the benighted scots...

Having lived in a few places, I'd say people everywhere like to generalise about other nations and tell themselves they know what 'those people' are like, I've done it myself a few times, and I've always been wrong when I did.