What comes onto is the vehicle. His property right does not extend to the inside of the vehicle.
"I will never asceed to the government, by force of law, and again outside of war or insurrection, telling me that armed individuals whom I would otherwise not want on my property,"
The matter involves an employee, that is not armed in the parking lot, or any part of the workspace. The employers decision regarding whether, or not the employee is welcome, is limited to workspace and work quality.
"As to OSHA, for the most part it is an overburdensome, governmental regulatory agency that sucks up untold citzens funds, and infringes on property rights."
It's justification is to protect the rights of citizens of the US, that would otherwise be violated by unscupulous employers. Regardless of the worth of any particular regulation, the govm'ts main job is to protect rights and OSHA is one such branch which does that.
For the record, in my own opinion, an individual, a company, or any other private organization should be able to establish the rules concerning who and what comes onto their property, inside the vehicle or out, inside their breifcase or out, inside their brown paper bag or out.
If folks don't like it, they are free to go somewhere else, get another job, or, violate the property owner's wishes and take responsibility for the consequences if they are found out.