Same Love was recorded and released before Macklemore's career even took off on a mainstream level. It was originally released for the proposition that went on the ballot in Washington, regarding gay marriage, that year and was dedicated to his gay uncle.
And upon it's release, all of the proceeds were donated to a gay charity organization.
Now how would that be anything of an "opportunist" situation when he was still practically unknown outside of Washington (give a take a few places where his name began popping up like XXL magazine, etc)?
