To be fair, part of the US government's job is to protect its citizens against outside threats. Given that, I can't imagine anyone inside the US arguing that they should stop spying on other countries' citizens. I'm pretty sure that's the NSA's actual job.

And anyway, there's a huge difference between being spied on by a foreign government versus your own. My own government actually has some amount of authority and influence over me and my community, whereas some place like the UK has little to none, so it's less of a big deal.