@IM-A-DEMOCRAT-BABY,
The brief history of Islam: Abraham (common ancestor to the "Big 3") had a dream in which God told him he was going to have a son who would make him the father of many nations. Abraham, being over 100 at the time with a wife not far behind, decided to try his younger Egyptian servant, Hagar, to sort of give God a helping hand. Product: Ishmael. Soon after his ancient wife actually had a kid: Isac. With a "real" son now the "bastard" son, Ishmael, was ignored and raised by Hagar on a mish-mosh of gods, combining the god that Abraham worshiped along with stories of the Egyptian gods. Ishmael went on to father a line of descendants that lead to Mohammad and Islam. Isac was brought up strictly on Abraham's belief and fathered the line of descendants that became Judaism which, in turn, gave us Jesus and Christianity. Ironically, Abraham indeed became the father of many, many nations ...and religions ...and wars...
Both Judaism and Islam are ethnically originated religions stemming directly from the same man in history. Thus, a Jew or Muslim can be either ethnic, religious, or both. As you might expect, Yhwh/Elohim and Allah have the same origins, and thus many of the same attributes. Both depict an all powerful, law and vengeance oriented deity, although the ancient Jewish prophets also attributed a coexistent softer compassionate side to God ...which Islam left out. Jews and Christians differ categorically on the subject of Jesus but otherwise worship the same god.
Just as the vast majority of religious Jews are Reformed Jew (read: "we think the stories and traditions are quaint and like taking all those holidays") with only a small minority that follow the orthodox faith, and the vast majority of Christians are only nominally so(read the same as the Reformed Jews) with only a minority who zealously adhere to the orthodoxy, the majority of Muslims are quite liberal in their faith and only a relatively small number of Muslims can be labeled zealots. These few are the ones keen on spreading Islam by killing everyone else.
As to whether or not Islam is bad I have this to say. My own limited experience tells me that the fundamental teachings of Islam are, in truth, quite violent. This I do not know first hand. I do know that any religion practiced for the sake of practicing a religion is useless and purposeless. Anyone, claiming any belief, who does not zealously believe it in their heart and apply the principles of that belief in their everyday life is nothing more than a pawn pandering after someone else's (probably political) agenda. Of those who are left, the question is of who is eternally right. It is a question that science cannot answer and the Truth has decided to not step forward in all glory to settle the dispute.