Has NASA "gone south"? Why are astronauts needed to explore the Moon's south pole?

Question

Wired: Why America Wants to Send Astronauts to The Moon's South Pole

“Before we put boots on the ground at the poles, we urgently need a robotic water ice prospecting mission to the lunar poles,” Burns said. “We don’t understand what the water ice looks like below the surface. Is it mixed mixed finely with the lunar regolith or is it blocks of ice? Both are theoretically possible, but it would require very different techniques to extract.”

The Trump administration’s plan to send astronauts to the lunar south pole is certainly bold, but before we make the “next giant leap” it might be a good idea to figure out what we’re going to do once we get there.

Gizmodo: Vice President Pence Gives NASA Five Years to Put Americans Back on the Moon—or Else

The US vice president's speech is linked in this answer.

As you will hear, in these recommendations, we will call on NASA not just to adopt new policies but to embrace a new mindset. That begins with setting bold goals and staying on schedule. To reach the Moon in the next five years, we must select our destinations now. NASA already knows that the lunar South Pole holds great scientific, economic, and strategic value. But now it’s time to commit to go there.

And today, the National Space Council will recommend that when the first American astronauts return to the lunar surface, that they will take their first steps on the Moon’s South Pole. (Applause.)

[...]And in this century, we’re going back to the Moon with new ambitions, not just to travel there, not just to develop technologies there, but also to mine oxygen from lunar rocks that will refuel our ships; to use nuclear power to extract water from the permanently shadowed craters of the South Pole; and to fly on a new generation of spacecraft that will enable us to reach Mars not in years but in months.

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The iconic 1962 We choose to go to the Moon speech includes:

We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard; because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one we intend to win, and the others, too.

Question: What would be the scientific, practical, or business utility of sending astronauts to the Moon's south pole beyond what a series of robotic missions could do at far lower cost? Is it an intangible, such as because it is hard or are there things the astronauts could do at the south pole that couldn't be done by robotic missions?

Answer 1

In his speech, Vice President Pence named one intangible and one tangible reason:

Last December, China became the first nation to land on the far side of the Moon and revealed their ambition to seize the lunar strategic high ground and become the world’s preeminent spacefaring nation.

And for more than seven years, without a viable human space launch program of our own, Russia has been charging the United States more than $80 million a seat every time an American astronaut travels to the International Space Station.

China claimed a "first" in landing on the far side of the Moon, while NASA has had to delay progress toward further lunar exploration via the SLS multiple times (Exploration Mission 1 was originally scheduled for 2017). Putting astronauts back on the Moon (one of whom could be the first woman on the moon) would be an answer to China's lunar mission in the public eye.

As for having to pay Russia to launch astronauts, the concern is not so much the current price of a Soyuz seat, but the rapidly increasing cost to NASA. Presumably the logistics of transporting astronauts to the launch site and arranging launches would be easier if NASA were able to launch manned missions itself.

Now, as for the benefits of a manned polar mission vs a robotic mission, there are only a few, and they're counterbalanced by the benefits of a robotic mission:

• Communication is currently limited with the Lunar South Pole; a robotic mission there will either require launching several communications satellites into lunar orbit or the development of an autonomous system. People are already autonomous, so the mission wouldn't rely on having constant communication between mission control and the astronauts.
• Lunar ice is proposed to exist in permanently shadowed regions in polar craters, which requires that solar energy is unavailable in those regions. As a result, a robotic system will require an onboard power system that can drive the robot, provide heating to critical systems, and drive a sampling mechanism without being replenished while in shadow. Astronauts only require food.
• There is a lot of uncertainty about how ice would exist on the Moon. If it is finely interspersed in the regolith, it may pose a problem to a rover if the rover enters a shadowed region from a sunlit region, causing the regolith water content to melt temporarily as it contacts the rover's hot wheels, become sticky, and refreeze while stuck to/in the wheels. This problem could be overcome with persistent heating of the wheels, but such a system would be a constant drain on the power source.
• Astronauts have all of the other benefits humans have over robots with regard to handling irregular terrain, being able to recover from falling over, etc.
• Perhaps most importantly, a manned mission could carry out the construction of a permanent lunar base, which would serve as a supply cache for future missions both manned and robotic.

That said, robotic systems have two major advantages over astronauts: they don't require life support and they can operate at an internal temperature of -80℉ or so without dying, unlike astronauts. As a result of the latter, a robotic mission could likely reach a permanently shadowed region where ice may exist on the surface. Such locations are probably out of reach for a manned mission due to heating requirements.

Answer 2

The answer to Space.com's Can Robots Build a Moon Base for Astronauts? Japan Hopes to Find Out is probably "Yes, but not in five years."

To add to @zaen's excellent answer one thing that a robotic mission can not accomplish is satisfying the following bit of US vice president Pence's 26-Mar-2019 Remarks by Vice President Pence at the Fifth Meeting of the National Space Council | Huntsville, AL (link found here):

And I’m here, on the President’s behalf, to tell the men and women of the Marshall Space Flight Center and the American people that, at the direction of the President of the United States, it is the stated policy of this administration and the United States of America to return American astronauts to the Moon within the next five years. (Applause.)

And let me be clear: The first woman and the next man on the Moon will both be American astronauts, launched by American rockets, from American soil. (Applause.)

Cued just before quoted statements: