I read a lot of arguments about how 'multiculturalism' and 'too many muslims' will lead to loss of social cohesion and lead to inevitable social conflict.

My thought is how come Europe managed to have CENTURIES of warfare (100 years war, 30 years, LOTS of civil wars, World War I, World War I and LOTS more) and most of these conflict were purely intra-Europeans? The Englishman in 1700 saw the Spaniard as being just as foreign as a Swede sees a Muslim today - probably more so if the Muslim lives in Sweden and speaks Swedish.

My point is just that if immigrants didn't exist people would still find something to fight over so this whole "immigrants are the very cause of social conflict" logic seems very dubious to me.