Says who? Why should I not be free to start a little company, and refuse to hire satanists, or neo-nazis, or left-handed redheads? You can call me anti-social--or even immoral--but what right do you have to decide my hiring policy for me?
We've got all kinds of laws on the books that prohibit that kind of discrimination. And they've been upheld as Constitutional.
More's the pity. Segregation was evil, but some of the measures taken to end it will have lasting, unfortunate consequences.
The key to your post is your qualification "little company." But this law was not limited to little companies, nor do I think there is a "little company" exception in the Constitution.
The law that was overturned was actually a step more indefensible than that anyway. It was not a law that prohibited discrimination. It was a law that AUTHORIZED discrimination. It said that you CAN discriminate against gays.
It's kind of hard to justify that under the Equal Protection of the Laws Clause.
If you've got a Constitutional right to discriminate, then you did not need this statute to do so. You only needed this statute if you did not have a Constitutional right to discriminate.