The fact of the matter is that people had sympathy with all the tenants who were being deceived by the LL (not by the LA who was also misinformed) because it wasn't their fault that they were paying for and making use of a facility that they weren't entitled to use.
They were also given a good period of grace so that they could make alternative arrangements rather than being evicted from the parking as soon as the land changed hands.
To be fair, it was only once some of those tenants became aggressive and abusive that sympathy evaporated. All these people needed to do was acknowledge the new status quo and direct their anger in the right direction and everyone would have maintained that sympathy with their situation.
Let's imagine the story had come here from the opposite point of view, say BL was a reasonable MNer and posted that for some time she'd been renting a flat with a parking space, at a price that reflected this. That it had come out after all that time, that the land didn't belong to the LL and that the parking had been secured at no notice and they now, suddenly, had nowhere to park. Alternatively she might have said that they'd asked for say a month's grace period in order to make alternative arrangements, but just been met with abuse and shouting from the new owner. In that instance I think this thread would've unanimously had sympathy with the tenants' situation.
I hope you're getting some peace and calm Mrs DC 