"The same is true for Latinos in the US, especially for recent arrivals."
Hardly. Latino "success," as if it's a bad thing, is based around whether they are here legally and whether they are educated here. It is also dependent on whether they are good English speakers in most cases. They are making their success possible through these things, not simply because there are more of them. They are fighting and assimilating simultaneously. Undocumented people don't have these opportunities until the second generation at the earliest, and even then it can be very difficult because they still aren't citizens. This is my whole point - citizenship is an opportunity for success in America as opposed to barebones survival, which, for some, seems to be an acceptable fate.
"Considering the vaccination deniers, I wouldn't be so sure"
Find me an example of a disease down their that causes massive death up here. Maybe west nile, but still, not even remotely close to the degree that smallpox decimated natives.
"The US has been quite stable compared to its neighbors to the south, but allowing people from those countries to enter unchecked will make the US the same as Latin American countries."
That shows a serious lack of pride and confidence in your own country. It's hard to claim you are a patriot when you think illegally low-waged factory workers in the South - employed almost exclusively by legal Americans, probably white Americans - are going to overrun your country, as if they have any power at all or care at all. All they're doing is trying to make it by and living day by day in fear of being sent back to Mexico and no longer being able to provide for their loved ones.