Erm, ISIL is being used by some British media, ISIS by others. Whats the big problem?.
The problem is giving a wider scope to their goals; putting them up on a pedestal to show respect. That goal is the “L” part, or Levant. This includes Israel, and would be a slap at Israel/Bibi. Figures that Ø and the regime he rode in on would be Isilized. Initially, at least, I thought Britain would just quote the US’s stance on “ISIL”, thus not take ownership of it. But, now Cameron has indicated otherwise.