Freedom of Speech

(an embryonic thought)
Has any one seen any discussion of the Snyder v. Phelps SCOTUS case (about the military funerals)which took the following approach:

The funeral is in some sense a private event which has some aspects of property. The Phelps are exploiting some other peoples property to advance their otherwise allowable speech.

One can make an analogy: You have a right to burn the American flag.
But you do not have the right to burn MY American flag! That is one that happens to belong to me!