It seems to me that it will be a horrible discrimination if naturalized citizens would be singled out this way, so it seems necessary to also strip citizenship from any US citizen by birth if he/she had developed problems with pledge of allegence or its parts ( e.g. 'flag', 'republic','under God', 'single nation indivisible', 'liberty', 'justice' or 'for all').
It is perfectly reasonable to expect loyal citizenship out of people who don't think there is a 'god'. Under the Constitution, the law cannot mandate that someone either except or deny the existance of a god. The Pledge of Allegiance" is lame. I've been an officer in the US military. My oath was to "protect the Constitution and the Nation from all enemies, foriegn and domestic". Allegiance to a 'flag', a piece of cloth, is absurd.
I say, dump the 'pledge' and replace it with something more substantial.