Depending on the chair, you should be able to auto-path onto chairs with the left mouse button (LMB). Some of the chairs/benches in Aven actually have accessible areas to get onto, but not all of them (I've tried quite a few before). It's kind of like the same way that certain areas on maps aren't accessible with WASD or the arrow keys but can be gotten to/passed through with LMB pathing instead.
Go ahead and give it a try on some chairs/benches, I'm sure you'll find that it works for quite a few of them.
Off note, I don't think I could have possibly repeated/implied the same things enough times in that short of a rant. Sorry about that.