Nonsense! Go in to hector the demonstrator (9)

I believe the answer is:

protester

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'demonstrator' is the definition.
(synonyms)

'nonsense go in to hector' is the wordplay.
'nonsense' becomes 'rot' (rot can mean nonsense or rubbish).
'go in' is an insertion indicator.
'to hector' becomes 'pester' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rot' inserted into 'pester' is 'PROTESTER'.

'the' is the link.

Can you help me to learn more?

(Other definitions for protester that I've seen before include "objector" , "Demonstrator" , "Person, we hear, not content" , "Demonstrating kind" , "I strongly object" .)

I've seen this clue in the Evening Standard.

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