Yes but see, this is exactly my point.
In France, as in many countries, civil union is open to everyone and creates the same rights as marriage (more or less, a few differences).
These people are not against that civil union (although most of them were probably against it when it was voted) or against gay people having the same rights. They are against the use of the institution of marriage.
As Jacknife said, bigotry it is. But homophobia ? I think it might be a shortcut to think that all these people are homophobic. There is no doubt that some of them are though, maybe in an important proportion.
On a side not, I cannot resist to show you a video of the said event because... well... you'll see... :
Edit : And now, I'm waiting for someone to post the Ultra Gay Seal... :D