Riskier? Didn't they all die. Maybe if you ended up with 2 stranded shuttle crews, but correct me if I'm wrong, and I probably am, but couldn't the shuttle fly without any crew?
There are rumors (that I've never been able to run down) that the astronaut corps insisted on this so the Shuttle could not be flown unmanned.
Bureaucratic requirements and institutional jockeying largely ballooned the Shuttle into something it was never supposed to be.
The outcome doesn’t determine the risk. I agree that this kind of office politics / face savings definitely is the cause of these two things.