This is just an asinine description for suicide bombers. These are people expecting to die for their beliefs. There isn't a shortage of descriptions that really can be applied to them, vicious, barbaric and murderous to suggest just three. To use the cowardly just devalues both language, whatever arguments you are making and any other words.
ISIS is Islamic
ISIS is clearly Islamic,(Very Islamic) they talk about Islam all the time and they follow large parts of the Qu'ran to great precision.
Islam is not ISIS. There are clearly a wide spread of views amongst those regarding themselves as Muslims and a vast majority are opposed to ISIS. That ISIS exists is no more the responsibility of most Muslims than the existence of the Westboro Baptist Church is the responsibility of a Church of England congregation in the UK (it isn't their responsibility).