Somehow doors are very difficult. They are slightly easier than USB drives, but they can still be tricky. Even when labeled, people mess it up for whatever reason. I think it's the pressure of walking up to the door and quickly realizing that you have to make a decision, but you're too deep into it to stop and read the sign. You make a choice. Fifty percent of the time that choice is wrong. Everyone inside the building look at you like you're an idiot, despite the fact that they did the exact same thing.
This reverse sign doesn't help matters at all. You can't help but look like an idiot when encountering this door. In fact, you have a better chance of doing the right thing if you just take a random guess at which way to go.