That the employer, in this argument, is trying to establish a property claim to my car. What do you think we've been talking about?
Then you're confused. He doesn't want any claims to your car whatsoever. He simply wants you to park somewhere else, and you insist on forcing your way onto his land anyway. By rights he should set up a fence and guard booth, and staff it with armed guards. Forcible attempts to enter his property should be met with swift and lethal force.
"That the employer, in this argument, is trying to establish a property claim to my car"
Not the case at all. His property, his rules, if you don't like them park in the street or find another job.