If the pizza place owners were black, and 2 people from the kool kids klub were getting married, and asked the pizza place to cater their wedding, and the pizza shop said no, would you guys be as outraged as you are now?
Obviously no one would be as outraged because the kool kids klub is a hate group and would garner very little sympathy for being turned away by businesses run by the same people they used to lynch. Hardly comparable considering that gays don't lynch Christians.
That being said, the pizzeria owners would be committing discrimination, but not a type that any sensible person would find very serious.