And shouldn't you support having as much information be available as possible, or do you want people to play games and try to hide info to raise prices on people?
You've got a parcel of land. You are farming on it or renting it or doing something which generates income. Because of that, you discount your future cashflows and determine it is worth X. Disney comes along and estimates that with what they are going to do the land is worth Y, which is significantly higher than X.
If the land trades for any value between X and Y, you are both made better off by the trade.
There is nothing wrong with you trying to capture as much of Y-X as you can, similarly there is nothing wrong with Disney trying to capture as much as they can. Neither of you are "owed" the money and there is no such thing as an objectively "fair" price.
Caveat emptor is a pretty terrible way to run a society. I'd argue if you deliberately misrepresent something as basic as who you are in a transaction in order to deceive your counterparty, that should be fraud.
If the land trades for any value between X and Y, you are both made better off by the trade.
There is nothing wrong with you trying to capture as much of Y-X as you can, similarly there is nothing wrong with Disney trying to capture as much as they can. Neither of you are "owed" the money and there is no such thing as an objectively "fair" price.