To give the current owners the chance to do the right thing, and make a small but reasonable gain from their property.
And to make it more palatable to the general public. It's a lot easier to convince people to go along with it if you're seizing empty unused properties that are only empty and unused because the owner refuses to rent them if they're not making excessive profit.
A filtered group that is selected to be favorable toward the representative, not hostile to him.
If they can't even get their filtered group to overwhelmingly support their positions, it seems unlikely that a general sampling of the population would.