You **can** respond to a user who edited your post using the `@reply` syntax. Quoting from https://meta.stackexchange.com/questions/43019/how-do-comment-replies-work:

> Notifications apply to the author, users with active bounties, commenters (associated to current non-deleted comments), and **editors** of the question or answer that you are commenting on

Emphasis mine.

It just doesn't include their name in the auto-completion box, that is all. The same FAQ page states:

> Tab name completion can be used, and that knows when `@name` is unnecessary and will then not automatically complete names. It also does not work for editors.