The trouble, which the article describes with some case studies on engagement before and after hamburger menu implementations, is that people who are not you are confused by it and don't understand it to be a menu.
fwiw, I've encountered this quite a bit when helping users switch from Internet Explorer to Firefox or Chrome -- both of which use the stupid hamburger menu -- an users hate it and "being able to find things" is probably the number one reported reason that they go back to Internet Explorer.
ed: for a more specific example, look at Firefox or Chrome, try really hard to imagine that you are a first time user of that web browser, but you've used IE before, and then figure out how to do one of the most common things that people want to do with a web browser: bookmark a page.