It is a case about higher standards of reasoning rather than deal with mutterings of people who haven't an idea how Newton hijacked astronomical language to suit his overreaching experimental science agenda.

In the case of Kepler, he along with most people at that time did consider why smaller objects orbit larger objects and why objects with no rotation don't have moons or natural satellites -


"The Sun and the Earth rotate on their own axes...The purpose of this
motion is to confer motion on the planets located around them;on the
six primary planets in the case of the Sun,and on the moon in the case
of the Earth.On the other hand the moon does not rotate on the axis of
its own body,as its spots prove " Kepler

Without being sidetracked by Newton's notion that the moon rotates, it is clear what is called 'gravity assist' provides a clear picture of orbital motions with going toxic and demanding that this reduces to experimental sciences.