It took me quite some time to figure out that Categorical Imperative is actually a complicated name for ideal society for all.
Thus, ideal action is an action which is ideal for all, since each person is treated as an end.
For example, not claiming ownership of anyone's body, and acting under such principle, is ideal for all.
We can imagine ideal society where no one violates the body of another, thus where all people are benefited by such principle.
Such principle contains no contradiction and is beneficial for all, thus by Categorical Imperative, such principle is best.
Any opposite principle would yield a contradiction, because if any person can violate another person's body, then such action cannot be practiced by all, since not all have ability to violate other people's bodies. Thus, any opposite principle would be impossible to follow by all.
Therefore, the principle of body rights is morally perfect and even most desirable one to have, since it lets every individual realize his wants under his own borders.