The most basic law of economics is that things are valued based on the “Law of Supply and Demand.” It is exceedingly obvious, all things being equal, that many people (due to view, sound, flicker, etc) would choose NOT to buy a home where there are wind turbines close by. (Whether they are right or wrong in their reasons is irrelevant.)
These beliefs would reduce demand, which clearly would have some negative impact on the price of such a property. Any report that concludes that there are zero negative property value effects related to wind projects simply can not be considered seriously. The only real question is how much of an impact?