More accurately, since it didn't involve fragmentation grenades but instead a thermite (heat) grenade, it probably can't be called a fragging. Somehow, "thermiting" just doesn't sound like a term that'll catch on. Still, from this article below the photo:

John Allen Williams, now known as John Allen Muhammad, center, plays the strategy game Risk during the Persian Gulf War in 1991. He was suspected of throwing a thermite grenade into a tent housing 16 of his fellow soldiers.



Ok, that's 2 known incidents in the last 30 years involving someone throwing one or more grenades into a tent, and both coincidentally were by Muslims. I happen to agree with this statement from the Muslim Public Affairs Council:

The troubling report of a U.S. soldier launching grenades into tents of his own brigade in Kuwait has disturbed all Americans.

A suspect has been apprehended and according to preliminary reports acted alone. This soldier should be subjected to a military court of justice and must now bear the consequences of his seditious act if he is found guilty of committing this crime.

We warn against exploiting this incident and making sweeping generalizations about others of the same race, ethnicity, or religion of the suspect.

We find no excuses, or acceptable motives, that can justify such a reprehensible act.

Well said.