Consumers' outrageous rudeness (3,5)
I believe the answer is:
end users
'consumers'' is the definition.
(end user is a kind of consumer)
'outrageous rudeness' is the wordplay.
'outrageous' is an anagram indicator (I've seen this in other clues).
'rudeness' anagrammed gives 'END USERS'.
(Other definitions for end users that I've seen before include "ultimate recipients" , "Rudeness in the ultimate consumers" .)