Actually, it is exactly what IS wants. So far, despite they have managed to unite the world speaking out against them, "speaking" is pretty key here. No signs of failing at the moment, nor any fatal weaknesses I know of. So by uniting the world against them, they can claim that every enemy is somehow allied with each other - which is arguably true - which provides to them a steady stream of recruits.
By being hostile to every government, they can garner the support of Sunni terrorists groups in/against these countries. They'll get Palestinian volunteers for being hostile to Israel, Moroccan-European volunteers for being hostile to the EU, Chechen volunteers for being hostile to Russia and the list goes on. So far, they can count more on the support Sunni Islamic groups from outside than they have to count on the reciprociation of hostility by the countries they came from.
This.
ISIS is a nihilistic organization. They are extreamly hostile against everything and only options are to join them or to be destroyed. Same applies to ISIS, to defeat everybody or to be destroyed.