A better general rule, I think, is that people should only eat when they're actually hungry. That could be in the morning or any time. I have an empty stomach in the morning(waking up around 6pm), but I don't usually feel hunger until between 10:30a and 12pm.
Even better, people should avoid the usual breakfast foods that are high in sugar and low in beneficial fats. I would only discourage people from eating breakfast if they're going to regularly eat foods that spike insulin and not exercise enough to compensate, in which case I believe they're setting themselves up for failure in the long term. A healthy breakfast, on the other hand, isn't harmful by any stretch of the imagination.