In short, the exhibit functions as propaganda for a Turkish government that is desperately attempting to rewrite its history, both of the distant past and of the present. After all, if beautiful objects can obscure subjugation and genocide in the past, they can help to falsify the image of a violent and repressive culture today, as well. Multi-ethnic has a comfortable ring today, one of those buzzwords like diversity and multiculturalism that project images of harmony and peace. Armenian, Greek and Arab Christians paid a head tax, under which families were forced to give sons into slavery. To label such a culture multi-ethnic is a bit like saying the same of an early American culture, because it imported and enslaved Africans and conquered Native Americans, enslaving some of the latter as well.
Image is all.
Of course, such things happened in Western Europe, too, but our history recognizes them. Imagine, say, an exhibit of the art of the Borgias that represented them as a nice, extended Italian family. What is false about this exhibit and its contextualization is what it ignores. Virtually all of the art is Islamic, most of it Arabic rather than Turkish, though the catalog makes it look the other way around. Islam is given lavish and due praise for its artistic productivity.