See, you lost me there. (Part of it may be that I’m having trouble parsing your first sentance - you don’t really mean that the Jews believe in the New Testament or the New Covenant, do you?)
The Jews, having separated themselves (via their purity, worship and dietary laws) from the non-Jews, didn’t neccessarily follow the same path and develop the same traits. They view themselves as the Chosen People and are in fact hard to break into and convert if you’re not born one (Not impossible, but a lot harder than the Jehovah’s Witnesses, for example). They’re certainly not actively looking for converts. The laws of “their” G-d don’t apply to the rest of us, and they’re not concerned with “saving” us.
Christianity developed between Judaism and Islam. So what I was saying was that some traits that may have been developed during early Christianity but after Judaism (prostlytizing, believe what we do our we’ll kill you and/or you’ll suffer everlasting torment, don’t wear white after Labor Day) could have been passed onto Islam.
Early Muslims, after hearing and accepting Muhammad’s teachings, perhaps did not discard the Christian idea that they were right, everyone else was wrong and should die and suffer torment for it. But my idea is that these traits were present when they were still Christians; they did not develop them independantly of Christianity. IANA religious historian, just wondering. If you say they developed from non-Christian paganism, that might be a different take on it. But that book doesn’t seem the most credible source. As a pagan myself, I don’t find the accusation of pagan origins all that credible *or *damning. It’s often used by lazy writers who are appealing to emotionality (pagan=bad) without finding intellectual or historical support for their assertations.
What would settle it would be accurate historical research finding that Christians before 600 AD were all peaceful, self-contained and religiously open-minded folks, and that these other traits could not have been bequeathed on Islam by Christianity but must have come from an outside source.
Whether or not these traits are “flaws” is open to debate, of course. But IMHO and YMMV, it bugs the shit out of me when people won’t let me believe what I believe in peace. I consider these traits flaws. And I do think that Christianity *and *Islam are together unique among the major religions still around today in perpetuating them, at least in scope.
But I haven’t heard of a Christian flaw that didn’t appear also in Islam, so to answer the OP, I don’t believe there are flaws that are unique to Christianity.