Your historical memory IS selective. Part of the problem did come from weak congregations which forgot radical gospel principles. But that’s not all there was to Christendom.
A gal I knew who had been Roman Catholic and switched to Judaism herself lamented the way that wonderful centuries in the history of Jewish and Christian coexistence just went right down the memory hole. Since she left Christianity she would seem to have no axe to grind there.
And think, what kind of “meshugas” would lead Christians to support things like the Balfour Declaration, if they were such evil monsters. They can’t even remember to hate Jews when it comes to what is the most important moment in recent Jewish history. Maybe the devil took a holiday?
Keep in mind, I do NOT have an axe to grind.
I cannot, however, tolerate the false belief that Christians have been, overwhelmingly, pretty hostile to the Jewish people for 1900 years.
Yes, there are wonderful exceptions, most notably the USA. But it is the exception.