OK. Of course you need to go in long races. The reason for early stops is simply being a bit coffee fuelled and very well hydrated, so having to empty is essential to comfort. As a male it's easy to stop or simply do the job on the move, downhill solo or pushing with a team mate on the flat. Of course, in really wet weather (like Carlisle-Blackpool in this year's ToB), there's no problem and no-one ever knows, the rain cleans you nicely, kit gets washed...get the picture?
As for the ladies, I can't recall being terribly interested, but they do have stops, just are a bit more discreet about it generally. Their races are not shorter for that reason, anyway!
The funny diagram seemed to need no-hands riding anyway, which is fine until something happens and you need a hand for the bars, which has all kinds of less than pleasant possibilities..
For whoever mentioned black shorts, well that might have been true, but not nowadays!
All this is probably why team mechanics pressure wash a bike before they touch it!