In reality, Islamist enmity toward the infidel West, such as was manifest on 9/11, is not a consequence of a small, unrepresentative group “hijacking” a religion whose “teachings are good and peaceful.” On the contrary, the kind of Islamist hostility that drove Islamist terrorists to act on 9/11 and all too many other occasions is deeply rooted in centuries of Islamic tradition.
He goes on to make the point that Muslims really are trying to take over the world.
I think there's a couple of things wrong with this perspective. First, looking through Islamic religious texts from a few hundred years ago is not a particularly good way of finding out what 1 billion people think today. If you look through the old religious texts of Christianity and, yes, Judaism, you will find much of the same sentiment expressed by almost everyone. Most, if not all, religions consider all other religions illegitimate, and would think it a good thing if everyone switched to their own. Even Judaism, which does not require conversion of non-adherents, espouses the belief that when the Mashiach comes, all will see its truth, and the Jewish religion will reign supreme over the entire world. It would be a big mistake to conclude from this, however, that Judaism really seeks to take over the world.
Second, I doubt most Muslims are aware of even a few of these texts, much less subscribe to and act on their contents. Following Rubinstein's logic would be like holding all Jews responsible for the opinion of R' Elchanan in one of his tshuvot.
Of course, there are a whole bunch of Muslims out there who do think it's important to kill people, but it makes more sense to think of them as crazy people than to assume they are representative of the feelings of 1 billion people. Most sane people do not find it tenable to kill for their beliefs. The fact that these few Muslims do should not make us think that Islam per se requires such an attitude, but that some crazy people, whose particular pathology happens to take an Islamic tint, do.
It's worth noting that religious induced violence is no stranger to any of the Abrahamic religions. I don't think that anybody would think it fair to say that religious crazies like Baruch Goldstein or Yigal Amir demonstrate that Judaism is inherently violent. And, of course, Christianity is no stranger to bloodshed. In fact, when considering whether it makes sense to think of Muslims in a conspiracy to take over the world, it may be instructive to ask from whom they are taking it. Probably the Christians, who have already taken it over. And how did they take it over? Not by giving out free candy. (Although that was definitely part of it.)