I do not know of any murderer who kills people for fun (except the mentally sick). All the criminals have a motive that to them is important. The Nazis massacred millions of Jews and others not for fun but because they followed a nefarious ideology in which those killings were perfectly justifiable. The communists in China, Cambodia and Russia also killed millions not for fun but for an ideology that justified all those murders. Muslims follow a similar ideology. They do not kill for fun but because of their hate laden belief in a savage deity and their blind obedience of a psychopath who invented that deity.  

The root of this problem is that Muslims divide the world into Muslim/non-Muslim blocks and are genuinely unable to see the oneness of mankind. From there on they become blind to all their own mischief and justify their own crimes in terms of “response to oppression”. Such oppression does not exist except in their wild imagination and it stems from the psychopathic mind of Muhammad who as a paranoid cult leader, distrusted anyone who disagreed with him and called everyone who did not follow his stupid claims enemy. Once that designation was made he justified murdering those perceived “enemies”, raided them without warning, killed their men, looted their properties and took their women and children as slaves.  

The problem with Islam is that its founder was a psychopath and Muslims are incapable of any rational scrutiny of their faith.