Not any longer. Now an oath is just a bunch of words. At one time swearing an oath was a sacred act. Now is just a string of words that no one pays any attention to. The person swearing has no intentions of adhering to it, nor is he expected to.
I suppose that a lot of people just believe in blind ritual.
When a person is ‘naturalized’ - a miracle happens! All of the protections of US law are bestowed on them. We would do the same for the rest of the world, but we are too lazy.