No clue if they are right. If they are, I can imagine it is because Mint would be stripped of any telemetry and other corporate bits of Ubuntu that Canonical has in there. From what I know, Canonical/Ubuntu does a good job of anonymizing that data and doesn't capture anything sensitive and put it over the wire, however in the worst case scenario of a coup, it probably doesn't hurt to be over cautious.
Although, assuming worst case. I personally say, OpenBSD.
Although, assuming worst case. I personally say, OpenBSD.