The gay people I know are not pushing an "agenda".* They are ordinary people who work, they are good citizens, good friends.
One lesbian couple I know have been together 30 years and they finally were able to marry. Now there is the legal right to be caring for end of life matters. One had children before they met, and now there are grandchildren. They are a fine family.
These people are not sinister. They are good to children, kind to animals. It would creep them out to hear you say that wanting to be married shows that they are furthering the legalization of child molesting and bestiality.
*Edit: Well yes--an agenda.But not "agenda" with a curled lip that some conservatives suggest. An agenda is simply a series of issues to be addressed. I this BAD in itself? Are wanting civil rights an agenda? Well, yes.