It's insensitive to call us out for nothing (7)
I believe the answer is:
callous
'it's insensitive' is the definition.
(similar in meaning)
'call us out for nothing' is the wordplay.
'out' indicates putting letters inside.
'for nothing' becomes 'o' (I can't justify this - if you can you should believe this answer much more).
'call'+'us'='callus'
'callus' going around 'o' is 'CALLOUS'.
'to' is the link.
Can you help me to learn more?
(Other definitions for callous that I've seen before include "Hard and unfeeling" , "Insensitive, cruel" , "Not feeling" , "Emotionally hardened" , "Cruel or unsympathetic" .)