Yes, it does defy the "once to select, twice to edit" rubric, doesn't it? Outlook is a bit of a law unto itself. But in spite of all that, it's a heck of a program and one of the very few Microsoft offerings that I can bring myself to praise.
If you don't want to go into edit mode, you need two operations instead of the one. First click, then hit ESC on your keyboard. Sorry about that! But it'll come automatically, soon enough.