The other way to look at it is that it's an arms race. Just because you believe something is problematic, that doesn't mean that stopping research into it doesn

The other way to look at it is that it's an arms race. Just because you believe something is problematic, that doesn't mean that stopping research into it doesn't lead into problems in its own right, and it can be hard to know what is the greater evil (but generally consensus has been it's better to be in control of that evil than to let someone else be in control of it and use it against you). I'm sure many of the scientists that worked on nuclear weaponry over the years weren't in a hurry to see their work deployed, but felt their country the more responsibly party to have that capability, even if just to keep level with others.