They'll killed countless innocent people and their sect of islam states to kill everyone who is a nonbeliever. So if we do nothing they will keep killing off more and more civilians. Also who cares if they get the sh*t beat out of them they attacked America and its allies and they'll pay.
In order to defeat ISIS, a combination of air strikes and ground forces are necessary. Although many countries including the U.S. and the United Kingdom are attacking ISIS, the scope of the attacks are not enough to end ISIS' reign of terror. As ISIS feebly holds on to what little power it has, the attacks it instigates will undoubtedly become more brutal, which may increase the allies attacks at some point.
Yes, extreme force should be used against Isis, just as Isis uses extreme force to rule its caliphate. The problem is people around the world are influenced by Isis, and they carry out bombings and shootings everywhere harming innocent civilians, as in the incidents in Paris and California. It isn't just Isis itself. If Isis utters a threat, the threat must be investigated and appropriate security measure put in place. Force should not be in the form of extreme torture. The U.S. should continue its mission in Iraq, using military strategy to dismember Isis once and for all.
Extreme force should be permitted and used in the war against ISIS. This terrorist organization is ruthless and does not care or have limits they won't cross in order to further their cause. Those fighting ISIS are losing many soldiers because we are fighting into their plan when we could obliterate them and show we mean business by using extreme force.
They have the right to do what they want. If they choose to battle or kill people that's their decision. Extreme force would only harm civilians. If the battle grows larger and more force is necessary then it would be justified, but right now it would do more harm than good.