"Here are two viewpoints concerning this:

The "system" knows that it can not directly advocate a manned Mars mission due to political opposition over perceived cost. Therefore it must call for something cheaper and then slowly morph it into a manned Mars mission.

---or---

A manned Mars mission is not on the table. The "plan" is really just a pork barrel exercise with no real goal. Conversation about Mars is only soathing nonsense to placate space exploration advocates."

Perhaps it's a little of both. But perhaps, "political opposition" is that there isn't a clear direction of how you send crew to Mars and get them back safely. Starting with obvious & simple things like what spot on Mars are you going to send the crew to. And other things like, what kind of booster are you going to use- existing hvy boosters, Shuttle C, or some large Saturn V type booster? How do you minimize risk from radiation. How do you minimize risk from zero gravity. Should you plan on a few manned trips to Mars? Should you plan on permanent occupation of Mars?
And perhaps the "soothing nonsense" is the bit about Pres Bush wanting the program to include more than a focus on the Moon. Meaning Bush wanted a program which was directed in the longer term towards getting crew to Mars.

Now, the Mars crowd always starts by saying they need a big launcher and they that a nuclear rocket would also be useful. My question is can you get to Mars using existing launchers? Can you use existing launchers and even not use a nuclear rocket or a nuclear reactor?
I say that Huge rockets require Huge demand in order to be efficent, and I say we don't currently have enough demand in order to make Saturn V type rockets efficent. I think that even the Altas V and Delta IVH could be too large to be efficent for current demand. NASA, if given the money, of course, can have a larger rockets built, but I think you are kidding yourself if you think this bigger rocket is going to result in a lower cost per lb delivered to Mars. So, the question is why does a Manned Mars need to start with Shuttle C or Saturn V or something even larger?
So, I say rather than have NASA spend billions developing some repeat of Saturn V, I think they would improve situation by instead buying Delta IV and Altas V by the cartload- and of course, get a "volume discount". One example of how you could use existing rockets is to make a small fuel production factory on Mars. According to Zubrin this is very easy to do robotically [if it's truely is a walk in the park, then this shouldn't cost much, 150 million for launch plus say 400 million for the rest of it]. So instead of bringing 6 tons of hydrogen, bring a smaller quantity- say a ton or two. Find some place on Mars that is a good area for exploration. Have a couple of rovers that use this fuel which is produced. Then land more Hydrogen, and have the rovers capable of bringing this fuel to the facility to be processed.
You could have a robotic camp which might have capability of deep drilling, sending rockets to other parts of Mars, or back to Earth for sample return and it could be developed so that it's ready for crew to land there. My point is that you don't need to wait for these large boosters which may take decades before they are built.