My parents lived up that way, and the amount of NIMBY-ism regarding offshore turbines is staggering. I suspect you may be right, and people just latched onto whatever claim got the turbines shut down.

It is also possible that they generate the sound of the same frequency, but coming from multiple sources it can compound in some areas to be louder than elsewhere - and those areas could change with the direction of the wind.

This is purely speculation from my side of course, as I've never been there.

No, it's a pretty safe bet that any of these complaints about wind turbines is just NIMBYism. It happens every single time.

How are those similar? What about this story leads you believe that these people are claiming to be hearing frequencies outside of those known by science to be audible to humans?