They didn't destroy the data [1] but regardless a migration path should have been provided. It wouldn't have been to much effort to check to see if they used the RSS feature and then basically tell them "this feature is not supported, but we see you use it - how about we make an export so you can use one of the other great readers out there". The upgrade from Snow Leopard to Lion did something similar when it decided to change the trackpad direction, so the functionality to notify the user is definitely there!
[1] Sorry: I do see that you mention that later on. Though, in general I'm not sure why so many HN comments think it did when the article said that it was still available?
[1] Sorry: I do see that you mention that later on. Though, in general I'm not sure why so many HN comments think it did when the article said that it was still available?