Above I was simply correcting a (perceived) geometric misunderstanding. We must also account for gravity. Remember that impactors need not strike either Earth or moon from the exact same direction that they approached the Earth-Moon system. For example, a comet which passes close to the Earth can have its trajectory bent by the Earth's gravity, so that it impacts the near side of the moon (coming from the direction of the planet) even though its path before did not go near the moon. The path of a body passing near the Earth will look approximately like a hyperbola with the planet at the focus.

Combine the above with the fact that impactors can come from any direction, and you see that on both Moon and Earth you could find craters in any location.