It's rather more complicated than that; let's not use the "Celt" word, though, as it's so misused as to be meaningless in this sort of conversation.

Let's talk about "Scots"; there is less doubt then as to what we mean. It's certainly true that, as England became more and more economically successful, many educated Scots began to worry about the increasing Anglicisation of Scottish culture (much in the same way that countries now worry about the enormous and distorting influence of American popular culture); people like Burns and his colleagues worked hard to establish and reinforce a "national" literatature and music to counter this. They drew for this on both "art" and "folk" traditions, and as a consequence the boundaries between -for example- art music and folk music in Scotland are far less obvious than they are in England.

The situation in England was rather different. Traditional culture was under threat just as much as it was in Scotland, but the perception of the situation was different. While in Scotland the process could be interpreted as a form of cultural imperialism and reacted to through cultural nationalism, that option was not available to the working classes in England. The process is better understood in terms of class than of nationality; the English workers were never the masters of a great empire. They were that empire's first colony.

The ruling classes had their own ideas about culture, and they meant "high" culture; the art music of mainland Europe. This, together with the mass of bourgeois popular music that became known as "national" music, was the model to which ordinary English people who wished to better themselves were taught to aspire. The music of the peasantry was considered, on the whole, to be quaint but childish; a thing to be put aside with other childish things, and studied as an agreeable hobby by antiquarians.

In fact, the divisions between popular and folk music in England were probably not particularly greater than those in Scotland; the perception, however, was very different, and that's what counts in the end. Regular attempts were made in England to re-incorporate folk music into the bourgeois art music model; John Gay in the 18th century, William Chappell in the 19th; Sharp, Vaughan Williams and their colleagues in the 20th. Without the option of calling on the kind of Nationalist impulses that see ones own culture being overwhelmed by another (identifiable as "foreign"), however, these efforts did not meet with the degree of lasting success that were achieved in Scotland. It was a political, class-based issue, but could not be put in those terms without attracting trouble. Scots could re-interpret it as a nationalist issue, but their cousins in England could not.

Without that focus, it is not surprising that the mass of English people have learned to despise their own traditional culture. They still have a strong taste for it, though; unfortunately they tend just to latch on to somebody else's rather than re-think their learned attitudes.