If private business owners want their private property rights respected (their ability under the law to not allow lawful concealed carry), while denying private citizens their second amendment rights (primarily in this case ccw for self-defense purposes), then they should incur an obligation (be liable) to provide protection for that citizen while they are on the private business owners property, specifically the area he has posted that denies the private citizen his or her second amendment right.
You can't have it both ways. In order to respect both the right to private property and the right to self-defense you have to respect both, and self-defense is primarily about the right to defend your ultimate private property, which is yourself (your person).
Liability is what you incur when you limit or restrict or violate someone else's rights.
Just like a gun owner that enters a store that is lawfully posted prohibiting carrying firearms is liable if he knowingly/willingly violates that policy and as a result someone is injured or killed he is liable, so also the store owner is liable if as a result of his no firearm policy one of his customers is injured or killed.
Remember, civil court is not criminal court - the rules of evidence are different, and in some cases, the rules of proof are different. It doesn't matter what the state law reads about this, civil courts interpret those laws differently in many cases from criminal courts, and those civil court decisions result in precedent established by case law, which is just as binding on people as any other kind of law.
Just my .02 on the subject.....