Finally, he says, "It was the policy of Islam to deal very strictly with polytheists of Arabia in order that everyone in the Arabian peninsula should feel compelled to enter into the fold of Islam; but it was very lenient to the People of the Book."  Then he quotes the rulings of a few companions who believed that the animals sacrificed in synagogues and churches were lawful to eat.

The basic idea lurking behind this speech is, as appears from some traditions, that Allah has chosen the Arabs over other nations and the Arabs were superior to others.  That is why they used to call non-Arabs as al-mawali (plural of al-mawla; clients) but the Qur'anic verses apparently do not agree with it.  Allah has said: O you people! Surely We have created you of a male and a female and made you nations and tribes that you may recognize each other.  Surely the most honorable of you with Allah is the one among you who is most pious...(49:13); a lot of ahadith giving this connotation have been narrated from the Imams of Ahlul Bayt (a.s.)

Islam while calling people to the right path had not put the Arabs on one side and the non-Arabs on the other.  It had put the polytheists - be they Arab or non-Arabs on one side, and they were given no choice except that they should accept Islam; and it had put the People of the Book, Arabs and non-Arabs alike, on the other side and if they did not enter in Islam, they were given an option to come under the protection of Islam by paying jizyah.  All that can be seen in this treatment is some leniency shown to them; but it doesn't mean that their slaughtered animals should become lawful to the Muslims when they have killed it according to their own custom and ritual.

As for the practice of fatawa of some companions, it has no authority at all in Islam.

It is clear from the above discussion that this verse does not show that the animals slaughtered by the People of the Book are lawful when killed in un-Islamic awy; nor is there any other proof to prove it.  If anyone insists on lawfulness of the animals slaughtered by them (because of the generality of the verse), then we have to restrict it to the case when it is known that the animal was slaughtered according to the rules of Islamic shari'ah, as may be inferred from the words of as-Sadiq (a.s.) quoted above from al-Kafi and at-Tahdhib:  "It is the (Divine) name which is important) and no one can be trusted in this matter except a Muslim."  Further details may be seen in the books of fiqh.