It's basically a line out of the Expanse series: if you make getting into orbit trivial, and if doing things in space becomes trivial, it becomes conceivable to redirect asteroids so they hit the planet, which would be bad for the people living there.

I don't know if it's a realistic problem, my guess is it probably is, but not significantly worse than what we already have with nuclear proliferation.

The basic problem is pretty real, though: we're at a stage of technical development where it's really easy to render the planet uninhabitable, while we're at an uninspiring level of cultural development that makes it really hard to produce sensible policy.