"it's not a bug, it's a feature" is sort of a phrase/meme referring to bugs that have been tried to not like a bug by PR departments. In this case, we see that

"it's not a bug, it's a feature" is sort of a phrase/meme referring to bugs that have been tried to not like a bug by PR departments. In this case, we see that this is a bug (iPads are supposed to be flat), but Apple claims "it's normal" to sell their device: classic "it's not a bug, it's a feature" attitude.