Islam as a religion for the Arabs

As I've been reading the book "Islam" by Karen Armstrong, I've been learning much of the early history of Islam and the various theological movements within the religion. Probably the thing that struck me the most was the Muslims' treatment of non-Muslims as the Muslim empire expanded. I was very aware of the practice of allowing the conquered non-Muslims to retain their religion as long as they paid the jizya tax. However, what I didn't realize was that the Muslims actually discouraged their new constituents from converting to Islam. Initially, Islam was viewed as a religion for the Arabs. Early Muslims believed Islam was for Arabs, Judaism was for the Israelites, and Christianity was for the Gentiles (I have no idea, Christianity was already so wide-spread by this point).

Many of the conquered peoples did convert to Islam but, initially, converts had to be adopted and sponsored by an Arab tribe, perpetuating the fact that Islam was a religion for Arabs. Since this is the case, there can only be two possibilities. Either Islam was seen as a closed religion and all others were damned or it was a closed religion and others could still be saved. From what I read, the latter seems to be much more the case; Islam was right but Judaism and Christianity, even with their corruptions, were still right enough. It wasn't until over a century after Muhammad that conversions of non-Arabs were finally encouraged.

However, a quick search on Google shows that Karen Armstrong has many many critics who accuse her of bending the truth to accomplish her own goals. A friend of mine had similar reservations about her as an author, having done much of his own studying on the subject.

In any case, aside from that book, I've heard, read, or had conversations that all stress a more universalist attitude and apparently it's having somewhat of an effect on me. Rather than thinking that there can be only one right path, I'm starting to wonder if there are different paths that all lead to God. Just as people can eat differently or exercise differently but still lead healthy lives, maybe people can also worship and practice religion differently but still be spiritually healthy.

I'm hoping this will be just the beginning of this subject and I'd very much like this to be the beginning of a multi-party dialog so if you have any comments or thoughts, please post them.