I generally agree with you -- I avoided stating that CS is more similar to math than the physical sciences for the sake of conciseness, and to highlight the science vs. engineering aspect.

That said, I find CS has some elements of what we generally think of as science. We can make hypotheses about unknown (and sometimes even quasi-natural) phenomena, and then test those hypotheses with empirical evaluation. The networking and Internet measurement literature is a good example of this, and I'm sure there are others as well (any measurement study, really). I don't think that's really the case in math.