You do know that last part was just a joke, right?
I've said it before that I can't really comment on internal matters, however, things like climate change are a global issue and the world needs America to help in tackling it.
As for Brexit, it's more complex then just immigrants. The UK gets far more from countries outside the EU - which we can control - than in it. To be honest, it's so complex, I doubt we'll ever really know...though, I would say the media over here are more right leaning so there's that. I was actually in the mind we shouldn't of had the ref as I suspect nobody can really know the damage and the "better out" notion is nothing more then crystal ball gazing.
Regardless of country though, I do wonder if a bulk of the immigrants did go would the work actually be done? Would Brits, America's etc really find people at home willing to work hard labouring jobs etc for little pay? After all, that's how capitlism works.
I think that's the real thing people are sick of. The problem is, what's the alternative.