In my experience, it's never the engineers nor the designers who makes those decisions. Stuff like that always comes from higher up the ladder, some middle management figure who thinks he is smarter than he is, mandates such abominations and refuses to hear reason from the engineers and the designers.

The engineers and designers then proceed to do as they're told because they like that nice fat paycheck at the end of the month more than they like the service they're building. Which is fair enough.