Leslie - You're very close to "hitting the nail on the head" when you say...
"...that can be stretched to cover almost any "need"...."
"...who decides who needs what and how people's needs rank in relation to each other?..." This is mistaken (IMO) - see below..

This conflict of ideas in Larken's essay has a few roots, but one of the main ones may not be obvious...
It is the misuse of the word ...NEED..
This can be a very dangerous word - It makes an objective claim, while offering very little information.
The word "Need" is a word that requires a "qualifier" i.e. a supporting or explaining word to go along with it in order to justify the use of the word "need." It cannot be allowed to stand on its own. Doing so invites danger.
As you likely know, in most day to day language, the word "need" may be replaced with the word "want."
Can you see the difference between.... On a hot day you say "I want an ice cream" or "I need an ice cream"
A few decades ago, most people would use the word "want."
When you "want" an ice cream, you are expressing a desire and people will know that you have a preference for an ice cream.
When you "need" an ice cream, you have said that it is imperative that you get an ice cream. No-one knows if you are expressing a preference, but it seems that there is an urgency that you receive an ice cream, and it takes priority.
When "need" is used like this, without a qualifier, there is no scale of needs.
Sure, you can have a scale of WANTS, but NEEDS all have equal urgency.

I said it can be dangerous - Here's why....
People will use the word "need" when they really are just expressing a want, in order to make you prioritise their desire.
Because of what the word means. It expresses necessity, a requirement, an imperative.
In this context It's obviously aimed at people's natural tendency to be empathetic etc.

Authoritarians use this to great effect.
e.g Nowadays it's unlikely that you'll hear a cop say that he wants you to do X or Y.
He'll say that he "NEEDS" you to do X or Y
I can guarantee you that more people would obey, or go along with the 2nd statement. (Psychological conditioning and all that kind of stuff).

Here's how it should be used. Whenever the word "need" is used, it should have a qualifier word along with it. e.g.
1 - I need a coat to stay warm today.
2 - I need a coat.
1 - I need an ice cream to help me cool down.
2 - I need an ice cream.
1 - I need you to get back from me so I can control you more easily.
2 - I need you to get back.

If we accept an unqualified claim just because the word "need" is used, then your question becomes "...who gets to decide what is needed... etc.."

(Obviously in day to day conversation between friends etc people will use this word in contexts where the subject matter is familiar to each person etc. but in debate or more serious type of discussions, it's worth being aware of these meanings above).
I don't know if I've explained this very well, but if you consider it for long enough you may find that it goes a bit deeper than what i said.