Why calling our enemies ‘Daesh’ can help to defeat them

From the letters page of the Spectator’s Christmas treble issue:

Sir: I was interested to read Sam Leith’s article in which he appears to argue that the language we use to describe those engaged in terrorism or the conflict in Syria doesn’t matter (‘Daesh? Sheesh!’, 28 November).

I wholeheartedly believe that the words we use are important, and they are particularly vital in the current bid to combat terrorism. If we are to succeed in tackling the extremist threat, we must do all we can to cut it off at source. To do this, we must undermine the legitimacy Daesh needs to maintain a steady flow of recruits.
 Referring to this group as Islamic State, Isil or Isis gives a veneer of authority to a brutal terrorist cult.

This terminology also associates the group with Islamic society, when the vast majority of its victims are in fact Muslims. It’s no coincidence that the majority of Arabic speakers in the Middle East now use ‘Daesh’.