(So, full disclosure, I struggle with this a little bit, mostly because of a lifelong fear of coming off as too pedantic.)
But man, imagine the message it would send if every major country in the Western Hemisphere, Europe, etc. decided to stop referring to the terrorist group as ISIS, or even ISIL. Because they aren’t a state. And they sure as hell aren’t Islamic. And there is already an alternate name they could use. One which is already in use throughout most of the Arab would. One which the group hates. Call them Daesh.
Here is a super detailed discussion of the pejorative origins of the name.
Here is a less dense explanation of the different names.
But basically, every time we called them ISIS/ISL, we’re giving them what they want. Daesh has started to catch on. France uses “Daesh” in its official statements. Kerry is using it now in the US.
What would it take to get major news organizations to start introducing the name? Or for other governments to start using it? I know it would be an awkward transition. But for my money, I feel like any resulting communication would be worth the symbolic victory.