No, I don't advocate for open borders. I'm fine with keeping out criminals, people who don't value our democratic system, or people who aren't interested in being productive members of society (e.g., NEETs - people not either working or getting educated).
> Your idea is borderline insane. ... someone on the left who lacks fundamental self preservation instincts ...
Huh. Well, checking, checking... I don't feel insane. I'm feeling pretty calm, rational, and evidence-driven.
The two big risks I see from large-scale immigration is this: - people who don't agree with liberal secular democracy. E.g., religious fanatics who want to enact a theocracy. That's all good; I'm fine with screening those out. - economic damage. But here, again, the economic data shows that immigration distinctly benefits the US, mostly through economies of scale, but also partly through higher-than-average rates of college attendance and entrepreneurship in 1st- and 2nd-generation immigrants, leading to higher earnings and innovation.
There definitely are also localized *negative* impacts from immigration, particularly for overwhelmed healthcare and education systems. These do not outweigh the national net benefits - meaning, the US still benefits as a whole - but I can understand that people living in those areas or culturally affiliated with them would be anti-immigration. But these are problems we could very much tackle if we wanted to: the federal government has more than enough resources to help these locales, while still getting the long-term and nation-wide benefits from increased immigration.
So: no, I flatly deny that I'm not concerned with self-preservation. Yes, I care about compassion and fairness, but it's quite reasonable to ask that fairness and compassion be balanced with self-preservation. And yet - even after considering self-preservation, we still benefit from increased immigration.