The odds of someone from this planet purposely deflecting a space rock to
hit Earth in a strategic attack are actually higher than one big enough to
cause destruction naturally colliding with our planet.

I recognize that some day an uncontrolled Earth-crossing planetoid or comet
could hit our world and potentially end all higher life forms here. But having a
bunch of big space rocks already circling us would be a very tempting weapon
for some radical groups, to be sure. Easier than having to go out into the
Sol system to find them.

They could be just as destructive as a nuclear bomb but without the messy
radiation - nice for someone wanting to move in and take over what's left
after the impact.