By vacant adjacent properties, do you mean properties bought up as "investments" by people who already have more money than they know what to do with, as well as a home somewhere else that they actually live in? You mention the "human rights" of property investors while ignoring the humanitarian needs of people who have just lost everything, in some cases including people dear to them, and who have nowhere to live. Vacant means empty and unused. Look it up. There is no-one peacefully enjoying the "properties" Corbyn is talking about. And I'm sure he isn't talking about doing it without compensation.