Believing the statement I made there is not limited to Marxists. I have found many anarchists believe the statement when challenged on private property (in products of labor) from an individualist anarchist perspective.

In a sense, Proudhon made a similar argument to Ellerman, but he did not fully draw the connection to principles of responsibility to ethically justify inalienability of that right. That connection is valuable because it makes it much harder to deny the conclusion