This seems flimsy, at least on Delta I don’t recall them ever promising a window. Maybe you looked at the seats and assume but I dunno.

I’m also not sure what damages these people really incurred?

You can’t even be sure of window alignment…

Seats 12A and 12F have no windows which are even viable. It should be stated in their seat maps since they are in the 'Comfort' section. Many other airlines include the window locations. As someone who flies often enough, and given a choice, I will never select them on the A321. I can understand how it would lead to a lawsuit.

https://www.delta.com/us/en/aircraft/airbus/a321