I would make these points:
a. The behaviour of other cyclists is irrelevant. Each of us is responsible for our own behaviour and we are not accountable for the actions of other road users who happen to use the same mode of transport.
b. The incident took place on a public road and whether or not the driver owns nearby land is irrelevant.
What is relevant are the actions of the driver and the endangerment he caused to another road user. If politeness is important to him, he should have just apologised and not tried to justify his bad behaviour.