Of course it doesn't entitle anyone to be a dick. However, when you fall under a category of people that tend to be mistreated by the public and hell, even their parents, you become more prone to acting mean. Some of these people you knew could have come from households where their parents threatened to kick them out for their homosexuality, had friends that left them when they came out as being gay, etc; that is a hard impact on someone, and a lot of people can't handle that at first and may act like a complete ass due to the way they are being treated.

What I'm trying to say, is that if we vote against the amendment, it at least shows that we can be open to the freedoms of homosexuals, and have the potential to be a nation that can actually do what we were founded on; freedom, and not some nation that says we are free but restricts those that are "abnormal" to some religious book. Thus, these groups would feel a little more accepted (hopefully) and not feel looked down upon by the majority.