Hardliners in way: mountain climbers leaving quietly (10)

I believe the answer is:

stalinists

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'hardliners' is the definition.
Both the definition and answer are plural nouns.
Perhaps you can see a link between them that I don't see?

'way mountain climbers leaving quietly' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'mountain climbers' becomes 'alpinists' (alpinist is a kind of mountain climber).
'leaving' indicates named letters should be taken away.
'quietly' becomes 'p' (p for piano and quiet).
'alpinists' with 'p' taken out is 'alinists'.
'st'+'alinists'='STALINISTS'

'in' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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