The idea that people can die does not provide much support here. It's easy to imagine doomsday scenarios for any technology or human behaviour. If you want to claim that a particular way of conducting R&D is reckless, it's on you to come up with convincing evidence.

Has human deaths ever prevented anything from being developed further?

Did we phase out guns, drones, bombs, nukes, fracking, etc.?

If there is money to be made, it will be made.