Why is Mrs. Carder Marrying a Lady?

A group of first graders at a school in San Francisco took a trip to City Hall to watch their teacher get married.
First of all, I think it's kind of strange for students to be at any teacher's wedding but in this case Erin Carder married a woman, Kerri McCoy.
Now I am not against gay marriage and I'm not against teaching kids about the gay lifestyle, so if all the parents of all the kids approved, then that's fine.
But there are a couple things here that make me a little uncomfortable with this circumstance.
I think a lot of people wouldn't mind if people were gay in their own personal lives, but there is a perception gay people are more open with their sexuality than heterosexuals. The word "flamboyant" comes to mind. And some even feel some gay people try to shove homosexuality down everyone else's throats.
Since I can't imagine a straight teacher having 18 kids at her wedding (even one at City Hall), this seems like a bit much to me.
Also, this was an official school field trip, that's totally wrong.
And more fodder for those who think a gay agenda is being pushed on our kids.