Well, the solution to other systems seems to be "it's checked in, therefore it can never be un-checked-in, so deal with it!" (or at least this is the attitude of some vocal proponents of them).
While I'm certain you and your organization have a perfect record of never checking inappropriate things into your git repository, mine does not. Even if all the employees at your company were perfect, there is still a chance of inappropriate information getting into the repository.