Be taken in by fellow in favour of embracing everyone (4,3)
I believe the answer is:
fall for
'be taken in' is the definition.
(thesaurus)
'fellow in favour of embracing everyone' is the wordplay.
'fellow' becomes 'F' (abbreviation - of a society etc.).
'in favour of' becomes 'for' (being for a particular cause).
'embracing' is an insertion indicator.
'everyone' becomes 'all' (all people).
'f'+'for'='ffor'
'ffor' placed around 'all' is 'FALL FOR'.
'by' is the link.
(Other definitions for fall for that I've seen before include "Be taken in by - romantically?" , "Succumb to attraction, or be taken in" , "Succumb to charm or love" , "Be taken in by - become infatuated with" , "Take romantic liking to- steady on!" .)