If this post received the comments, how did they get moved? Is this a fair practice?
When two threads are covering substantially the same story, we often merge them to prevent split discussions and to prevent duplicate posts on the front page. Is it a fair practice? That's for you to decide. I think it is! Actually the community tends to get annoyed if we don't do it.
This is just standard/boring forum moderation. HN has done it for many years. Moreover we do it so often that if there were even a slight tilt of community opinion against it, we'd never hear the end of it. That's how I know the community likes it.