Qutoting Rishonim about Christianity would not totally be correct because before the Reformation christinity was mostly either Catholic or Orthodox which has one doctrine. After the Protestant Reformation which began in 1517 there was a schism in christianity about theological ideas. Wars were fought over these ideas and while we might think they are insignificant obviously they did or they would not have fought all these wars.
If you want an example , see what some evangelicals think of the Pope and you might be shocked how little esteem some have for him. Icons are also not present in many forms of Protestanism and I dont think they exist in the largest denominations in the US of Methodist and Southern Baptist