“He believed Gabriel was gay and to him that was a bad thing. He did it out of hatred for a little boy.”
The case, which started in 2012, saw a baker refuse service to a gay couple for their wedding.
The protesters held signs with slogans including “Homo Sex Is Sin” and “Jesus Can Save You And Set You Free From Your Sin”.
Attorney General Loretta E. Lynch says the law violates the civil rights of trans people.
Music icon Melissa Etheridge married partner Linda Wallem over the weekend in California.
The success of the Modern Family (gay) wedding on TV comes in time with a recent poll that showed acceptance of gay marriage in the US is now in the majority.