There are two rejection issues here:Paññāsikhara wrote: Interesting thing is, we are still doing the same right now. But nowadays, many schools will outright reject the literature of other schools, and hence discussion falls into sectarianism, and worse. "Only this is true, all else is false!"
1. Completely rejecting literature of other schools (which clearly has a long history).
2. Completely rejecting literature of one's own school (e.g. Abhidhamma and Commentary), which seems to be a particularly modern idea and is perhaps more prominent in Western Theravada. At least that's my impression. (To be over-simplistic about it: I don't see Chan/Zen Buddhists calling Bodhidharma mixed up the way some people talk about Buddhaghosa...)
Regarding the rejection of literature of other schools, isn't it arguable that for those of us don't have the time for a PhD-level study of these issues it might be more productive for us to practise according to a particular school and not get distracted by trying to figure out all the connections? My attitude is not so much: "I reject all these other schools"; but: "If I tried to seriously study all of the schools there wouldn't be any time left to actually practise..."
Sorry, that's getting a little off topic here.