People who dismiss the significance of this horrific statement are totally missing the point.
The issue is supposedly "gay marriage", but it's really about basic human respect. If you respect someone less because of their sexual preference, that's as bad as respecting them less for their skin color.
The statement is incredibly stupid and heartless. It's akin to expressing even just a hint of reluctance for allowing black/white marriages, because "if we have no laws on this people take it to one extension further... does it have to be humans?"
Anyone older than 12 should have the sense to not think this, let alone say it.
"Know what you know, know what you don't know, and understand and appreciate the distinction."