Yes, and you don't get to determine those of someone else.
If your religious obligations prohibit you from serving the freaking public equally, then here's an idea, don't work with the public. This guy wants his cake and to eat it too. (Pun maybe intended.)
Also, unless said baker absolutely refused to bake cakes for divorced people, obese people (gluttony is a sin after all) and adulterers, you know the things the Bible also prohibits, then he/she is a hypocrite. Which I'm fairly certain Jesus spoke out
against. Christ like behavior indeed. If said religious warrior was really serious, they would follow their own standards to the letter. I have yet to see evidence that this is the case for this particular baker.
People will use your products for things you don't approve of, it's a little something called "retail." That's just how the industry works in general. Like aww, poor baby, you served a couple you don't fully approve of. My heart freaking bleeds. As we say where I live, harden the F up.
And there are some, including some I worked with, who refuse to touch pork products. I, or another employee without such obligations, would handle the pork so as not to offend their religious obligation instead of, as you've worded, throwing a temper tantrum about what they felt compelled to do or not to do in service to their god.
And said people were adult enough to presumably choose a profession that would not include such things. Or spoke about it with management so as to not to deny service to customers of the public for their own quibbles, thereby inconveniencing the public. You know, being responsible for your own life and not interfering in other people's lives. That kind of thing.
This person chose the job, was there a gun to their head demanding they become a baker? No? Well then suck it up and do your job.
Or at least put a sign up that says you won't serve bla- oh I mean gays. At least then no customer will be embarrassed by such an incident, which is like the first rule they teach you in customer service. Don't inconvenience or embarrass customers.
You're there to serve them, not pry into or pass judgements upon their personal lives.