It is both, and one of those things is unconstitutional.
Let the memorial stand, but modify it in such a way so as to bring it into alignment with law. Those who died in WWI were not fighting the Crusades.
In recent history, we've had a POTUS announce a call to "crusade," completely ignorant of the resistance this created against his own troops. More than any, our "leaders" need to be sensitive to the REASONS that our Constitution specifically barred government from religious endorsements.
Our government can no longer afford to uphold religious symbols tied to wars, not in our rapidly evolving, technological era. They need to evolve with the times.