To argue otherwise shows a lack of moderation (7)

I believe the answer is:

outrage

I'm a little stuck... Click here to teach me more about this clue!

'a lack of moderation' is the definition.
I can't tell whether this defines the answer.

'to argue otherwise' is the wordplay.
'otherwise' is an anagram indicator.
'to'+'argue'='toargue'
'toargue' anagrammed gives 'OUTRAGE'.

'shows' is the link.

Can you help me to learn more?

(Other definitions for outrage that I've seen before include "Shock grossly" , "furious reaction" , "scandalous!" , "Deplorable insult" , "abuse" .)

I've seen this clue in the Sydney Morning Herald.

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