Isn't the point that He doesn't physically exist? At least, not in a physical sense as we know it.
If He did, He could be measured and bob's your uncle, end of argument.
I thought likening Him to a political belief was pretty accurate. People don't need to see Him to base their whole way of life around Him. He exists because they believe he does. He's impossible to measure.
I agree, he doesn't physically exist at all, and that belief in god is akin to belief in a political idea - both beliefs are so deeply ingrained they are essentially impossible to change. I also agree that it is more than likely that our failure to measure him is due to the fact that he doesn't exist.