Please...
As you can see, the crescent has been utilized in design for some time. If your going to gripe about something, at least gripe about something worthwhile.
Yes crescents have been used as symbols before. That does not mean that radical Islam isn't trying sneak their symbol into the memorial. Islamic crescents are not the same as natural crescents like you would see on the Moon. Islamic crescents are usually a circle within a circle because they want to distinguish their crescents from other crescents.
From Wikipedia:
"Note that in the case of an astronomical crescent, such as the moon observed in the sky, the outer arc will be 180° (a half-circle as previously mentioned), while the Islamic crescent symbol (Arabic هلال hilāl) is often shown with an outer arc significantly greater than 180°"
Crescent
When a person is facing into a crescent in a mosque, they are looking in the direction of Mecca. The same is true of the memorial crescent. It is aligned with Mecca.
You can call it griping if you want to but Obama and his kind are using Islamic crescents as their logos. To them it is a victory to sneak their symbolism into our government. Just like the mosque they want to build at Ground Zero is meant to be a symbol of their victory there.
Do a search for "stylized Islamic crescent"