Kelly knew before abuse reports that Porter would be denied security clearance

Which begs the question why would a four star general keep someone on staff that he knew wouldn't get a security clearance? A person seeking to enlist, who will never have access to material as sensitive as that Porter had access to, would be denied entry if they couldn't get a security clearance. Kelly needs to resign, have his security clearance pulled, and never be allowed to have one again.

The man was unable to get a clearance but had access to everything the President has access to. Whose side is Kelly on?