On the other hand, what if someone refuses to rent out a property to someone that has a poor credit record, or is a felon? What if that person happens to be black? Does race supercede common sense?
I purport that race should not be a deciding factor in any way - period.
Clearly, there are limits, but your example is faulty. The landlord in your example has no scruples about renting out property, they are using unlawful and immoral discrimination to use mere skin color as a premise for whom they will and will not rent out to.
The doctor who refuses to perform abortions refuses them for everybody. Males, too.
All I'm asking is, where's the jurisdiction? What you described is a thought crime. Thought crimes are considered common, now. But are they legal? What about the 1st Amendment? What about property rights? Should minorities have special rights superior to non-minorities? Who decides, by what criteria?
We have a doctrine of negative rights in this country - whatever isn't specified as a power of the government, isn't - and everything else is legal. Where does the constitution prohibit a racist from using racism to decide who to rent his property to?
When the country was founded, there was an acknowledged distinction between the roles of law and morality. Laws were to be moral, but not all morality was to be codified, because it was impossible to get common agreement on all morality everywhere, or to do so without losing freedom.
So you say, "There is probably a limit to how one applies his conscience towards refusing service to others." Indeed, there probably is - now. All I'm asking is, where does it get it's jurisdiction?
Don't count on the law restricting your ability to "discriminate". I saw my old landlady Leona Helmsley EMPTY ENTIRE BUILDINGS with little more than a bag of cockroach eggs.
You should control your property and as properly read you have a right to discriminate - free association.