What does ethnic diversity have to do with universal healthcare
I've heard this "talking point" time and time again with no kind of explanation behind it
In a country with a high amount of ethnic diversity, members of the majority ethnic group are more likely to resent the idea of socialized healthcare because they feel it will benefit minorities and take money from them. This isn't a "race card" thing either, it's true.
There's a huge racial disparity when you look at the percentage of people with no health insurance. The demographics in the US are such that blacks and Hispanics make up about half of the uninsured in this country despite being only around 30% of the population. Because of this, when you talk about something like universal healthcare or even the ACA, many whites view is as being taxed to pay for black/hispanic people's healthcare and thus resent the idea.
In countries that are more racially homogenous (such as, say, Japan) this is less of an issue and thus the population is less opposed to socializing services such as healthcare.