As I said:

When these feuds break out people go back and dig up ancient reasons to justify them

So they say now that "we're doing this because a thousand years ago their ancestors did our ancestors dirty", but there were periods in between then and now where it was water under the bridge and people got on with their lives.

If you think that people in those regions have literally been killing each other every day for over a thousand years, how is anyone actually left at this point?