what a stunningly pretentious and ignorant thing to say.
reasons to be tired and drive: rotating shiftwork, working multiple jobs, caring for a newborn, caring for the sick. that covers millions of people, off the top of my head, without doing any research. and those are only the most black-and-white examples. more ambiguous cases include: driving from physical activity like OP mentioned, long drives to visit friends/family, events like weddings.
if you want to make the argument that sleepy driving is more dangerous than we give it credit for, then we can talk - but thats not what you said. "You should never get behind the wheel if there's a chance you'll fall asleep!" is an absurd thing to say.