I don't think this applies to hiring/firing people.
If someone doesn't want to do work for gays for moral/religious reasons, do you really imagine that they would what them working for them for the very same reasons? The employer becomes the coconspirator, enabling gays to pursue their immorality when they could employ wholesome moral family type people. I mean there once was a time a man could be fired for cheating on his wife and no one blinked an eye.
Are Christians just as eager about not serving people who worship idols, or people who drink, or people who have straight anal sex, or people who use the word "God" in vein, or people who work on Sunday, or people who don't honor their parents, or people who covet their neighbor's wife, or people who have lied before, or people who are divorced, etc, etc, etc?
Why is it that Christians are only concerned about not serving people who are gay and nothing else listed above? Seems hypocritical.