I understand what Wallingford is trying to do, but he's going about it the wrong way. Let the courts decide when specific performance is the proper remedy.
Overall, this isn't a detestable legislative pursuit. Imagine a gay-bashing Christian fundamentalist wanted his daughter to have special wedding dress designed by her favorite designer. The dress designer is gay and refuses to design a dress for a Christian fundamentalist.
Are you really going to force a gay designer to use his talents to further the happiness of someone who offends him? If so, you're part of the problem. Wallingford actually believes they should have the right to refuse.
The right approach of the gay designer would be to make his homosexuality clear to her. I figure that she might have some questions about gays based upon her parents' stereotypes.
Obvious answers to unstated questions:
1. No, I did not choose homosexuality.
2. I thoroughly loathe perverts who abuse children.
3. God made me, and he made me gay.
4. I know of gays and lesbians who have very firm belief in Jesus Christ as Lord and Savior.
5. Jesus had nothing against homosexuality except against temple prostitution of any kind.
6. Your father and boyfriend trust that because I am gay I will not seduce you.
7. We ask only for equal rights -- not "special rights".
8. Children are not sex objects.
...Ultimately the antipathy to homosexuality will die as conservative-leaning businessmen discover that homophobia is bad for business -- much as was the case with antisemitism and racism.