Taash vs Culture [DATV ACT 2 SPOILERS]

I am around half way through the game and I wanted to talk about a personal quest of Taash, in which you have to tell them that they should either embrace the Qunari or the Rivaini culture. That whole idea is just bugging me, we have no option to tell them to embrace both. In general, I don't understand the whole idea behind it? I get that they struggle with their identity but plainly telling them to either be Qunari or Rivaini feels like lazy writing. What, people of multicultural background have to choose one or the other culture? Really?