When Mr. Zalmen Jaffe printed the English Tanya in England, he was unsure whether he should have an English translation of the end of Perek Alef, where the Alter Rebbe speaks about gentiles.
The following is a summary of the Rebbe’s response:
Since the Tanya has already been printed in many other languages, there would be no point in taking it out. Furthermore, one doesn't have to be a kabbalist to see that the Alter Rebbe was correct in his assessment, for all the nations of the world were witnesses to what was going on in Germany, and the countries it overran yet remained indifferent… Putting all this aside, If we are dealing with a goy who wants to keep his feelings to himself and not make trouble, he will not make an issue of it. If he is the kind of goy that wants to make trouble he can create issues without looking for them in books, as in the case of the Blood Libel, which you cite in your letter.