How to express the reason for scolding someone

Question

Edit: added previous context

Maruko has just asked grandad if he would save her from a wild dog. Grandad is scared but doesn't want to say 'no' to Maruko.

I thought my problem was only with the last sentence, but now I'm confused about who said the penultimate sentence too.

「まる子、おじいちゃんを混乱させるのはおよしなさい」
Mum: Maruko, please stop confusing grandad
「でもおじいちゃんの意見をききたいんだもん」
Maruko: But I want to hear grandad's opinions
見ると、友蔵(grandad)は「わしは...わしは...」とうなだれた姿で、さらに深みに入りこんでいた。
Narrator: When she saw the figure of grandad hanging his head and saying "I..I..." she probed more deeply. (who is she?)
「こらっ、もういいの。おじいちゃん、もう考え込まないでくださいよ」
??: Hey! Enough of this! Think harder.
質問をしただけなのに、おかあさんに「こらっ」なんて怒られる筋合いはないとまる子が思った瞬間、おばあさんがとりなすように言った。
Narrator: Even though it was just a question, the moment Maruko thought that there was no reason to get scolded by mum for saying a thing like こらっ, grandma intervened.

This is my translation attempt. I have two problems:

1) The なんて particle seems to cover a multitude of confusion here. For starters I guess it's replacing the quote particle と and there's an implied 言う. But secondly, it must be replacing something that gives the meaning of 'for'. I can't fill in the blanks here because I don't know how to say 'get scolded for a given reason'.

2) It isn't logically consistent. If Maruko didn't see a reason to be scolded why did grandma need to intervene?

Answer 1

You're confused as to who says 「こら」. It's not Maruko, but it's her mother. Besides, こら is not a word that a little girl (that Maruko is) would say (at least in the presence of her parents.)

Maruko asks a question, and her mother responds with こらっ and nothing else and then we're at the current sentence.

質問をしただけなのに、

"I only asked a question"

おかあさんに「こらっ」なんて怒られる

"Yet mother became angry at me, saying こらっ"

筋合いはない

"She had no right to do that"

とまる子が思った

"or so Maruko thought"

瞬間、

"at the moment Maruko thought so"

おばあさんがとりなすように言った。

"Grandma intervened thus"

なんて is a particle expressing Maruko's disbelief, that she got shouted at even though she only asked a question. It replaces と but I don't think there's anything left unsaid. The mother shouted at Maruko but neglected to give a reason Maruko could understand. Grandma, however, is irritated by the mother's こら and is intervening.

"I only asked a question, yet I got scolded for no reason I can see." The moment Maruko finished her thought, Grandma intervened (by saying something you aren't showing us.)

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I must say that I don't quite understand the context so I'm a bit out on a limb here (so someone correct me if I'm wrong), but your translation of the previous sentences has a few issues too.

見ると、友蔵(grandad)は「わしは...わしは...」とうなだれた姿で、さらに深みに入りこんでいた。

Narrator: When she saw the figure of grandad hanging his head and saying "I..I..." she probed more deeply. (who is she?)

"Who is she?" Well, it's granddad that's the subject of the second half of the sentence.

"When she (Maruko) looked at granddad again, he was hanging his head and was going deeper in (into paralysis/thought)"

「こらっ、もういいの。おじいちゃん、もう考え込まないでくださいよ」

??: Hey! Enough of this! Think harder.

Mother (to Maruko): "Hey, enough of this!"

Mother (to Granddad): "Snap out of it (stop thinking)!"