Government recognition of a deity does not translate to the establishment of a theocracy.
"In God We Trust" is more a way of we, as men, proclaiming that we understand that there is a higher power to which we are subordinate (be it a single monotheistic icon, or the cosmos personified), rather than assuming we are the top dog in the existential plain. The inclusion of "God" doesn't necessarily imply state devotion to Christianity, but rather serves as a place holder for any other interpretation of a cosmological presence greater than mankind.
If the motto did in fact seek to establish a state church, the President would be quoting Bible verses to justify executive orders and vetoes, which of course is not the case.
Inb4 no one reads my post because it is more than one line.