"Human Rating" existing design = total redesign
"The Human Rating is just minor adjustments of the flight profile, so that the rocket doesn't exceed human G force maximums during the flight to orbit. To declare that it would be a complete redesign of either the Delta IV or the Atlas V doesn't know what they're talking about. "
That is completely and utterly WRONG. For one, you simply can't "make minor adjustments" to the flight profile to significantly change it. Rocket science doesn't work that way... The entire structure was designed and built around the specific loading of the flight profile it was designed to fly. You just can't "slow it down". You get your flight profile FIRST, then you get your loads, then you can BEGIN to design your structure AFTER you know it's loading profiles. Going backwards is pushing rope.
Also, the strength and fracture margins are COMPLETELY different for man-rated structures. I know EXACTLY what I'm talking about, it's what I do for a living. By the time you add enough weight to have the required margins and safety factors for manned flight, your payload on the Delta IV and Atlas V go to ZERO. Redesign and reanalysis time alone would be LONGER than starting a brand new program from scratch, which is EXACTLY why we didn't go that way when the new programs started 4-5 years ago.
BTW, the vehicles of the Mercury and Gemini program were NOT man-rated by current standards. They weren't even close.
Just think about new building construction vs complete renovation of an old house. Any person who has done it will tell you that renovation to update a house and bring it up to code is MUCH more expensive and time consuming that just plowing it under and starting from scratch.