Obama is a "Reform Druid"

The Atlantic had a really odd posting that was apparently meant to be a joke, but wasn't funny.  Jeffrey Goldberg indicated that President Obama is a "Reform [sic] Druid" which means he "only worships shrubbery."  I don't get it.  At least Mr. Goldberg capitalized "Druid."  See the entire bit at:

Is Obama a Muslim? - Politics - The Atlantic