People can set their own policies on their own private property. Are you seriously trying to tell me that, if you're visiting my private home or business, I don't have the right to set policy regarding who can carry firearms on my private property.
The Bill of Rights, including the First and Second Amendments, are limits on the powers of government, not private individuals.
An individual's private property is just that, and said individual has every right to set policies on the bearing of arms thereon, and I'm not aware of any court case which has ever said otherwise.
It's patently ludicrous to assert that a person can't set such policies regarding those who they allow onto their own private property...
I am saying that you can tell someone to leave your property for any reason. You have no Constitutional recourse to confiscate his gun on your property or to have him removed because he is armed. You can require him to leave or have him removed because he is trespassing and has not your permission to be on your property. It is a fine distinction but a necessary one.