I find this troublesome as well, but I think it has to do with the underlying technique: the blockchain makes it impossible to change or edit anything after a week or so....
In the first few days after you post something, you can still edit it but after some time the edit button dissapears: the message will be there forever as it is never to be changed anymore....
This is really frustrating I admit.
I am not sure if it wil ever be possible to change this.
This is also the power of the blockchain technique in the case where it is used in cryptocurrencies: the whole "chain" of transactions is permanent; nobody can change the old transactions anymore after they are done.
This makes it an enormous safe system for transactions and contracts, but maybe we must come to the conclusion that it is not good for writing things that should be dynamically changed.
I think there is a way out. https://github.com/steemit/steem-js/issues/130
Maybe, they will allow you to do that in a simpler way in the future.
I really hope it does, because I think the whole problem with the editing will hold people back from posting content once they find out this handicap.
Not only if one finds a misspelling or such thing, but also if there are links in the post that have become obsolete, many ( serious ) content posters will want to be able to edit these older posts.
I do want to do away with some videos that are no longer relevant to the history, but I'm unable to edit it.