However,i am for the cultural exchange of ideas. Often times interesting ideas become assimiliated by one culture and are used appropriately and in line with the cultural makeup/character of the culture assimilating them.
I am too, but if it is made into a mass movement like immigration, we do not get the best of each. Rather we get some of the good, some of the bad, and a requirement to centralize control and regulate everyone uniformly thereby obliterating the diverse and cultural aspects we originally sought to appreciate. This is multiculturalism in the modern West at its most benevolent. At worst, cultures are trivialized as mere consumer products and its people as pawns in politics and as more easily exploitable labor. For example, community colleges now offer Chinese language courses not for understanding and respect but for its mechanical utility in economic exchanges as in telemarketing and so forth.
Cultures would be better served and conserved if they were left to themselves as a rule. Mass tourism, trade, and immigration would probably need to be reduced, but archaeologists, anthropologists, historians, diplomats and any other official business types could carry on as before.
If someone has genuine interests in cultures other than their own, they will make a profession of it and dedicate their lives to it. This was always only relatively few people. The rest of the ostensible diversity lovers will tend to have other, less noble or productive motives.