Crass act? No! Strangely seen as beyond criticism (10)
I believe the answer is:
sacrosanct
'beyond criticism' is the definition.
(I've seen this in another clue)
'crass act? no strangely' is the wordplay.
'strangely' indicates an anagram.
'crass'+'act'+'no'='crassactno'
'crassactno' anagrammed gives 'SACROSANCT'.
'seen as' is the link.
(Other definitions for sacrosanct that I've seen before include "above criticism" , "Inviolable" , "Unchallengeable" , "Too valuable to be changed" , "protected" .)