The real issue is why is ANYONE allowed to keep security rights to an organization that you are no longer a part of?
In the private sector, you lose those rights the minute you are terminated.
Former high ranking govt players are sometimes called in at a moments notice on current issues, with no time to renew a clearance.
Example: Say there’s a CIA station chief who has worked on Country X his entire life. He retires. There’s a flare up, and though his replacement is good, he doesn’t have a lifetime of connections and contacts. You call the old guy in to help out. If the FROG (friendly retired old guy) has kept his clearance, you can spin him up instantly. Getting a new clearance takes months.