I don’t see a contradiction here. If control is out of the hands of decision makers, that’s a supply chain risk . Were it not for that, the service is seen as critical to national security.
I dunno, safeguard seems like a weasel word here. It’s just reserving control to one party over another. It’s understandable why the DoD(W) wouldn’t like that.
I'm pretty sure you (and others) are trying to apply some kind of guess at the "supply chain risk" designation, but it means something specific.
Here's the term defined in an official context:
https://www.acquisition.gov/dfars/252.239-7018-supply-chain-....