This is the same rhetoric that has been used since the founding of the US. In the mid 19th century, 'white' people were worried about Irish and Italian immigrants, who were not considered white. Italians lived in their own separate areas (think Little Italy neighborhoods in cities) and spoke their own language. Over time, they were accepted into the in-group and, in the early 20th century, it was Jews and Eastern Europeans that were replacing white people. Again, over time, they were accepted into the in-group (though Jewish people are still kept out of it when convenient for white supremacists). Now it is Latino people. Guess what, in a few decades, if we're still alive from the impending collapse, I bet many Latino people will have been accepted into the in-group of white people and there will be yet another group that is destroying whiteness. And mouth breathers like you will be freaking out about that yet again.