Most ancient (and even modern) pagan religions are ethnocentric, nationalistic, and even xenophobic. That's because ancient pagan religions were essentially tribal (and later civic and/or national), the purpose of which was to secure the real-world protection, prosperity, and posterity of the whole family/tribe/community, not the individual. Chinese ancestor-worship and Japanese Shinto are still essentially this way, though (currently) non-aggressive, but also essentially indifferent to the fortunes of outsiders. They also have no problem with blatently favoring their own over outsiders. This is because pagan religions tend just to be an affirmation of nature and biology (plus a lot of superstition and obsession with luck and evil spirits) which, as Dawkins showed 20+ years ago, is decidedly "genoistic": the likelihood/willingness of an organism to sacrifice itself for the benefit of another organism is inversely related to their genetic proximity. (It also explains why when most people see a fight between a shark and a dolphin or between a chipmunk and a snake, most of us root for the mammal.) In this way, early religions simply follow typical human practice of looking after ones own and leaving outsiders (termed "not-people" in most ancient tribal societies) to fend for themselves. The dividing line was on how one dealt with the outsider when he is no longer "somewhere out there" but comes among you and yours. Many societies and their religions have treated such strangers as marks/prey as matter of course. Others - particularly those where inter-tribe trade was important - had highly developed - even excessive - morals concerning hospitality: the stranger among you was (so long as he behaved himself) to be treated not only as an equal member of the community, but was in fact to be protected at ALL costs! (see the story of Lot offering to let the Sodomite mob rape his daughters rather than his guests: this was the level to which the Ancient Near East stressed the sanctity and inviolability of guests.) Of the principle "world religions" these days, Christianity, Islam, and Judaism all have doctrines against "mixed marriages" (strongly discouraged but not absolutely prohibitted). There is nothing explicit in Buddhist scriptures against such (though Buddhist societies - and even more so Buddhist MOTHERS - are another matter. (Up until about 20 years ago in Southeast Asia a Buddhist woman who married a Caucasian or a Negro and/or a non-Buddhist would be disowned by her family and her village.) As for Hinduism, as there is no ONE Hindu religion, but rather thousands of cults and at least 4 yogic paths, attitudes vary from place to place and school to school, but were (and still are) primarily limited by caste. Christian teachings on dealing with non-Christians (Christian heretics and excommunicants aside) is to afford them every courtesy and consideration you would a brother in Christ. Also, while Christians are called to call their fellow Christians to account (point out their sins (lovingly and following scriptural procedure) and call them to repent, Christians are specifically interdicted from attempting to so "discipline" non-Christians. Christians are called to establish RIGHTEOUS (i.e., not necessarily Christian) government and uphold RIGHTEOUS leaders, and to - within the law - work to unseat the wicked from positions of power, though this is wholly secondary to and indeed derivative from the directive to preach the Gospel and make disciples of all men. Jewish teaching is similar to the Christian teaching, but the limitations of Kosher and Sabbath laws effectively put "a hedge" around observant Jews. Also, while it is contrary to the Torah to lend money at interest to another Jew, lending at interest to Gentiles is permissable. (Jews get around the first prohibition anyway by each party forming a company or bank (which not being a person can't be a Jew) and the companies and banks to the lending and borrowing at interest, which is perfectly in accord with the letter (if not the spirit) of the Torah. Islam specifies that "Infidels" are to be treated differently than than the faithful. The Koran teaches that pagans/idolaters are to be given the choice of "convert or die" while Christians and Jews within "the realm of peace" (the lands under Sharia law) are to be treated as second class citizens - forced to pay a 20% excize tax and forbidden to make converts or say, write, do, or display anything "insulting to Islam or its prophet" ... such as displaying crosses or pointing out that Mohammed clearly did not know - let alone understand - the Torah or the Gospel. Apart from that, however, "the people of the Book" aren't to be molested. In "the realm of war" (the lands NOT subject to Sharia Law), however, all infidels are enemy-aliens who can be preyed upon - robbed, kidnapped, enslaved - with impunity. However, Moslems who are actually living in societies "in the realm of war" (as opposed to those who just go on raiding missions there) are instructed to act honorably, morally, and responsibly, and to live lawfully, and to always be decent if not actively charitable neighbors to the unbelievers in their civic community. They are to be good citizens.

Try studying the Bagavad Gita (the song of the Lord) with a group of people that understand it. It will open your mind's eye to the beauty of all religions, rather than starting a big war of words over what ancient passages can mean.