dehumanising enemy is something employed by tyrants in war. islamically the concept of rats and dogs is just not applicable because these species donot deserve a human treatment. where as even if (and this a is a big if) you are completely in the right and the opponent completely in the wrong, dehumanising is essentially wrong cause it leads to war crimes, loss of right of prisoner of war and absolute down hill from humanitarian rights.
You have to dehumanize the enemy a little bit, otherwise it becomes harder to kill them as has been the case in pakistan. This is why we have had so many peace deals which have emboldened the talibs to this point.