You are correct that in wh- noun clauses the normal word order is Subject, then Verb--the same as in statements. Thus the standard word order for the example sentence would be
One has only to watch the efforts of children who are starved of love ... to realize how desperate their need is.
So why do people use the inverted word order, as in Moon's example?
The first reason is to avoid putting the verb at the end of a long noun phrase subject (not the case with Moon's example). This is because if the verb BE comes after a long noun phrase subject it loses some of its strength.
Here are some examples from Google of inverted word order with noun clauses containing a long noun phrase subject:
... [His] carrying a young infant on his back while in combat was when I realized how serious was his digression into insanity.
--He saw early and clearly how brilliant was the work of his fellow Southerner and how lasting his achievement would be. (Note here that the second noun clause has the usual statement word order.)
... As I grappled with the causes and consequences of the internal conflicts on a daily
basis, I realized how serious was the suffering of the vast majority of these fleeing people...
The second reason relates to Moon's example, which has a short noun phrase subject, "their need."
Inverted word order is used when the noun phrase subject is short if the clause expresses a subjective or evaluative idea. Adjectives in this kind of clause are judgment words like "brilliant/desperate/serious/important."
Here are a few examples from Google:
... and it was not until their trenches began to give way under the terrible hammering of the French artillery that they realized how DESPERATE was their situation ...
--Ah, how STUPID was the world before you graced us with your infinite wisdom :-) (an ironic comment on a discussion group)
--Once the Fox technicians saw how IMPRESSIVE were the first rushes, they abandoned the second camera unit that was filming non-anamorphic..
--In Nagasaki he met the Dutch and went aboard one of their strange ships. In his ensuing travels he saw how DEFENSELESS were the coastlines.
--I saw how INADEQUATE were the resources in their excellent attempts to respond and I saw the refugee camp in Kisoro,...
Finally, inverted word order in noun clauses is characteristic of older literary style; it is found in the Bible:
--As Jethro remained in the camp, he soon saw how heavy were the burdens that rested upon Moses.
Other literary examples from Google include
--They stood quite still and looked at the forest,
saw how high were the great cedars,
and gazed upon the entrance to the forest.
There, where Humbaba was wont to tread,
was a fine path; straight it was and easy to travel.
--Taras saw how troubled were the Cossack ranks, and that sadness, unsuited to brave men, had begun to quietly master the Cossack hearts; but he remained silent.
--The great army of the North-kings moved boldly up the hill; and, when they saw how few were the Burgundians, they laughed and cheered most, lustily...