There is no comparing ritual prohibitions with moral prohibitions. Christians argue that taking the life of a human fetus where the mother's life is not endangered is immoral. And so do religious Jews (and Muslims) and many secular individuals -- because the issue of abortion is a moral issue. Contact with dogs, on the other hand, is a ritual issue, not a moral issue. Which is why non-Muslims do not consider it immoral -- unlike the many non-Christians who consider most abortions immoral.
And Christians and others who deem abortions immoral when the mother's health is not threatened have as much right to argue for passing laws banning most such abortions as other citizens do to pass laws banning racial discrimination.
Ah, the skeptic may argue, but what if Muslims deem human contact with a dog (except, according to Muslim jurists, for security purposes, farming and hunting) an immoral act, not just a ritually prohibited act for Muslims?
If indeed such were the Muslim argument, we would have an example of an unbridgeable difference between a Muslim conception of morality and that of non-Muslims.
There is then no analogy between Christians wanting to use the democratic process to ban a practice regarded by hundreds of millions of non-Christians as immoral and the Muslim ban on human contact with dogs, a practice regarded by no non-Muslims as immoral.
The appropriate analogy to Muslim taxi drivers refusing to take passengers accompanied by a dog or carrying a bottle of wine would be religious Jewish taxi drivers refusing to take passengers eating a ham sandwich or Mormon drivers refusing to take passengers drinking alcoholic or caffeinated drinks.
But such Jewish or Mormon examples don't exist (and if they did, religious Jews and Mormons would regard such persons as crackpots). They do not exist because Jews and Mormons do not believe that non-Jews are required to change their behavior owing to Judaism's or Mormonism's distinctive laws. Religious Muslims, on the other hand, do believe that wherever applicable, non-Muslims should change their behavior in the light of Islam's distinctive laws. And that difference is at least as important to Muslim-non-Muslim relations as the vexing issue of violent Muslims.
As for the difference between fundamentalist Muslims and fundamentalist Christians, a Christian mailman in Denver called my radio show to say that despite his profound religious objections to pornography, he could not imagine objecting to delivering even the raunchiest porn to homes that ordered it. First, religious non-Muslims, especially in America, believe that liberty, too, is a religious value; that is why Christians put a quote about liberty from the Torah on the Liberty Bell. And second, they have no doctrine that holds outsiders bound to their religious practices.
And that is why there may be more to be learned about the future of religious Muslims' relations with non-Muslims from Muslim taxi drivers than from Muslim terrorists.