Actually it does not violate civil rights, except for the right of the proprietor to serve whomever they wish.
As an example, a nightclub or restaurant can have a dress code. Under the law it is permissible to discriminate by virtue of clothing.
SW-User
Making a sign is not the same as making law. There are dozens of examples of merchant "signs" and rules that have no legal standing whatsoever.
There is now a system of anti-discrimination laws enacted by federal, state and local governments. The entire United States is covered by the Federal Civil Rights Act of 1964, which prohibits discrimination by privately owned places of public accommodation on the basis of race, color, religion or national origin. Places of “public accommodation” include hotels, restaurants, theaters, banks, health clubs and stores. Nonprofit organizations such as churches are generally exempt from the law.
The right of public accommodation is also guaranteed to disabled citizens under the Americans with Disabilities Act, which prohibits discrimination by private businesses based on disability. I would assume you wouldn't want merchants refusing to serve all people in a wheelchair.
Remember the customer can spend their dollars where ever the want. The business owner can only make the business attractive to potential clients. He can choose to lose clients.
If the client has a bad attitude, they still get to buy a product and spend money. They may have to go to another business
If the business owner has a bad attitude they can wait and wait for clients that have received the goods and services else where.
It isn't political that the signs disappeared it is basic economics.
It's illegal. You can not deny anyone service unless their behavior violate common laws of decency . How would you like it if you were to walk into a business and have someone deny you service because they don't like the color of shirt or your style of shoes. It's your business but as long as your a licensed operator you have to conform to the law.Who would you want to deny service to, anyway just on a whim. After all, you're making a profit off that person.