You already can delete some of your old posts or edit old posts. You cannot "delete from the blockchain". Why promote that meme when you know it's not even plausible or feasible?

I think Steemit should make it easier to delete from their front end (as an account owner). If Steemit can delete from their front end some content then the account owner should be able to push one button to have all of their content removed from the Steemit front end. On that feature I think yes implement.