you're right Tumor. It's not hurting anything. Well, it obviously hurt someone, or they wouldn't have made an issue out of it. Overall, though, you're right. It's harmless.
However, it WAS brought before a court. So what if the person brought it up was a whiner. It got there. So the court didn't say "oh, you're just whining, get over it." The court actually took the case seriously. They looked at "under God" in the context of the Pledge and interpreted it to be a federal endorsement of religion. (I agree 100% in that it is a federal endorsement of religion. Read Eisenhower's quote from 1954 when the words were added to the Pledge.) The court then ruled that this endorsement is in violation of the 1st Amendment.
It's not the popular decision, that's plainly obvious. Based on how I interpret the reason for the addition of the words, plus the fact it is the proper noun God and not the common noun god (big difference, IMO), I see the addition as a federal endorsement of a specific deity (the one from the Jewish/Christian faith) which is even more of a reason for the Pledge, as written since 1954, to be in violation of the 1st Amendment.
Does this fact even hurt 0.001% of the US population? Probably not. It does NOT matter in the grand scheme of things. However, it is still, IMO, a violation of the 1st Amendment as it is, once again IMO, a federal endorsement of religion, specifically the Christian (or less likely, the Jewish) faith.