Short answer: The moral high road matters.
Long one: We kept saying it over and over during the election. "Why are we voting on civil rights? We aren’t supposed to be voting on this." So, why is it okay now?
Well, I get the "it’s the only way to win" argument, but I still don’t agree with it. I don’t believe in winning at all costs, especially at the cost of others. Because, as soon as we promote voting on civil rights ourselves, we open Pandora’s Box. We lose the ability to claim outrage at it. When the next group loses their civil rights to a majority vote, how can we then say "we never should have voted on that", when we promoted that very thing. We cannot have it both ways.
But, that other thing we lose is the ability to fight this. This has happened once. Once can be an aberration. Once can be fixed. Twice? Twice becomes problematic, because the second case can now refer to the first as precedent. Three times? Now, this is "the way we’ve always done it."
Winning or losing is not really the issue. We could probably win on this. If not in 2010, then in 2012. But, then what happens in 2014? In 2016? Do we have to do this every two years? Will we win every time? Will people meet, fall in love, propose and then have to wait for the election to see what happens? Or hurry up and get married before the election, so they don’t have to wait two more years for this to happen all over again?
Okay, now this is only my argument over what could happen to same-sex marriage. What about everyone else whose rights could be put out there? The trans community comes to mind. What if someone proposed a constitutional amendment banning the changing of your legal sex? Could that pass a popular vote? Transgender people are even less understood than the LGBT community, even among LGBT people. A radio show host in Sacramento even said that if he ever had a transgender child, he would "beat his son with one of his own shoes". He also said "I look forward to when they go out into society and society beats them down." He and his co-host dedicated a half-hour of their show towards gender dysphoric children and all of the ill they wished them.
When confronted with what they said (and a heavy loss of advertising), the two hosts defended it as a joke and denied doing anything wrong. A glance at the half dozen comments on there put half in each camp. So, half of the people on there thought that there was nothing wrong with advocating violence against a child, and a few invoked it as a First Amendment right.
Do you really want to chance that going up for a vote? (While I realize there were only three comments against these children and for the radio hosts, in my opinion, that is three too many. That there were only six comments and fully half thought the hosts did nothing wrong and one even said they would boycott the advertisers that pulled their ads? Well, that chilled me to the core.)
The courts need to decide this. Maybe they will be smart enough to know that the correct answer is equality, maybe they won’t. But, more than one amendment was trashed on the way to this mockery of a law, so I think we have a chance. At least we won’t be following bad with bad.