I would call myself a cultural nationalist and i don't expect to change people's views via arguments.
Culture based nationalism does not get support or opposition because of stats or logic. Your views on it are share entirely by your personal experiences and your personality.For example if you live in a urban environment where you get to meet lots of educated and intelligent people of different backgrounds , you normally will welcome more of the same and look down upon people who are alarmed by aggressive pro-immigration policies. Similarly if you live in a environment where you are exposed to bad parts of different cultures and see multiculturalism tearing your local communities apart you will obviously support culture based nationalism.
For me the distinction between cultural based nationalism and race based nationalism is irrelevant. If you obsessively spend time removing racist thoughts from your head then yeah it could be huge distinction. The rise of racist/xenophobic sentiments is directly proportional to the rise of multiculturalism because large scale immigration will lead to the arrival of not just highly skilled diversity but also the kind of diversity which people who live in segregated urban environments are seldom exposed to.
If people think Trump is an extremist then they are stupid because the kind of extremism and division that highly diverse societies with communities having high incompatibility produce is going to be exponentially more extreme than that. My prediction is that we are going to see parties based on racial identities emerge for every race and political ideology will stop mattering altogether. At least we won't have people whining about pronouns at that time.