Labelling anybody that supports protecting the definition of marriage as "hateful bigots" is indeed dehumanizing the enemy. Dehumanization is done so that you can with a more clear conscience rail against them (not just their positions).

You may think that basing their political position on the bible is stupid and wrong, but throwing around "hateful bigotry" as the underlying motivation for the positions they take is indeed the dehumanization I was talking about.

It has been a very effective tool, as always. Anybody that thinks marriage should be restricted to a man and a woman is automatically "filled with hate". I've heard this or a variation of it thousands of times. Any opposition to changing the definition of marriage is decried as motivated by hatred. It is the rallying cry against opponents of gay marriage. It is exactly the kind of labeling used to make those who oppose you into something other than humans with a very different point of view. On every side of every dispute there are people that do this.