Space travel is not safe and never will be, you can always get randomly sideswiped by a piece of debris in LEO and that's that, even if everything goes perfectly. If the astronauts understand the risks involved then I would say it's their call. Living on Earth isn't safe for that matter, driving has a 1 in 100 chance of death throughout your lifetime, so that margin isn't significantly more given that you get to go to the frickin Moon.
I don't really buy the "if they die, it strands human spaceflight for years out of PR reasons" argument since what that argues for and against has the same result: nobody goes space for a while. In the end there will always be someone willing to roll the dice. ESA is already playing it 100% safe, that niche is covered.