This is really about CIVIL rights so then the emphasis should be on CIVIL union rights, not marriage rights. Gay people, my advice is take the word "marriage" out of your campaign, and fight to get state laws changed so that the licensing process allow civil unions for any two adults, which gives everyone the same civil legal rights.
Let the religious have their term marriage. Religions still have the right to deny gays the option to marry, but there are many churches who will marry gays, if gays choose that route.
I think alot of people in the gay community would be suprised if they knew who was going into the voting booth and voting against same sex marriage. Often people say one thing to your face or seem supportive, then in the privacy of the voting booth do something far different. As long as the religious right can steer the issue to the ballot box (and they're doing a masterful job of it) marriage equality is going nowhere. Civil rights should never be handed over to voters, but the right has turned it into a work of art in this case. It's working for them, and they'll continue to do it.
Again, you're arguing for separate but equal. It's a really bad idea for gays to go for 'civil unions that are just like marriages'. The anti-gay movement is losing ground every year and it's only a matter of time until gay marriage is legal nationwide. The younger generations are overwhelmingly supportive of gay marriage, and once the baby boomers die off gay people will be home free.
The surest way to make it so that you can never muster sufficient support for true equality however is to aim for something that's 'close enough'. If I were them I wouldn't settle either, especially when you don't need to as time is on your side.