You are in every way ignoring the normal procedure, just as the author of this unmitigated drivel is.
I was in a battalion S2 shop in the early eighties, and then with various classified electronics classifications up until after the Soviet collapse. I knew men who worked in the Pentagon, and with various civilian weapons development projects.
Separation from the job has ALWAYS been accompanied by loss of the clearance.
There isn't any need to justify clearance revocation. It's generally been automatic.
What the idiot who wrote this crap should have been asking was who had somehow granted these people a clearance that they shouldn't have had.
My understanding is clearances are good for 5 years and must then be renewed. Separating from government service and going to work for beltway bandits has a higher value if your clearance is still, “good” otherwise the company has to pay for a renewal investigation.
I imagine a cabinet level official who has even higher clearances, retains that clearance even if the, “right to know” is limited.
I do believe it should end upon termination but, I don’t believe it does at that level of power. While they no longer have the right to know they can be shielded from prosecution if information lands on their laps.
As with everything I post, I could be wrong,