"Every nation gets the government they deserve"

I agree, because the government and culture of a country is largely an expression of the beliefs of the people within it.

So doesn't that mean that people from countries with bad governments are importing their culture when they immigrate? If I moved to Saudi Arabia for work, I would not teach my children that it's good to behead atheists, so why would I expect Muslims to do the reverse? I would hide my beliefs to fit in... And so would they in America.

And are Hispanic governments not famously corrupt?

Geography and geopolitics are strong factors, but if all the Central Americans traded places with all the citizens of the USA, I think the values and cultures of each country would be expressed in their new geographic locations. The more Mexicans enter the USA, the more the USA becomes Mexico, since government is an expression of the governed.

People carry their culture with them. They bring their level of education, their values, and their deeply held ancestral religions.

This film made a caricature of the nationalist on the podium without showing why someone might actually hold those beliefs.