As to the reasoning that one can just ignore the "So help me God" portion of the oath; so then what's to stop a person from ignoring any other part of the oath?
The argument being, either swear to the oath in its entirety, or you can pick and choose to not "swear" to anything you don't like in it.
How this oath can be used to criminalize and/or convict with punishment for betraying or violating the oath is to me the main concern.
However, like others here have mentioned, just re-institute the exception clause and make it clear that no other part of the oath applies to it. I don't have the time or the wherewithal to argue the legality or the legal consequences of allowing this exception, but it sure would be interesting to hear the Air Force's reasoning behind their removing it.
Besides, swearing an oath, as far as I can throw a logic bomb, is just some gobblety-goopy formality that a person needs to perform to gain membership for most and is clearly not the compelling reasons they volunteered to begin with. As an example, just how seriously is an 18 year old kid going to take that induction oath when, for the majority of them, that oath is forgotten the moment the ceremony is over with?
And for the truly ardent patriot whose intention is to give his whole being, his entire life, his every waking moment to the cause he is swearing to, the oath conveniently represents something to stake his purpose in life to.