“There was a Christian alliance which defended Europe from Ottoman/Muslim onslaught.”
Because Christianity is congenitally anti-racist, any Christian alliance that defends race defends it only accidentally, not as the main point of the alliance. Christians in those days would have been glad to accept Muslims as their Christian brothers and intermarry with them if they had agreed to convert. Some of them did. See Shakespeare’s play Othello for a literary depiction of this.
This is shown in another way by the nowadays little-acknowledged fact that Christianity first expanded to the east before it went west and conquered Europe. Christianity penetrated as far as India and China before many of these outposts were overrun by the Muslim onslaught centuries later. So there never was any racial barrier as far as Christianity was concerned.
My point stands. Christianity is anti-racist, and anti-racism is obviously toxic to the continued existence of the white race, because it encourages race mixing and hence its extinction.