Which is, if you don't know it...
We pledge allegiance, to the flag
Of the United States of America
And to the republic, for which it stands
One nation under God, indivisable
With liberty and justice for all.
It's a few things that make people having objections to saying it. Here.
By the way, the 'under God' line wasn't added until 1954.
But... it does say "In God we Trust" on your money (at around roughly the same time the Pledge was changed too). Are people suddenly opposed to use physical currency? Not having the Pledge just strikes me as odd. Kind of like if you didn't have the national anthem. It seems sort of important.
Personally, wouldn't have a problem with them changing either of them though. The "under God" part seems really out of place. And I prefer "E pluribus unum" over "In God we Trust". But, that's how they are right now and I think they should be presented as such.