I think that people use such inflammatory terms too loosely, without actually being aware of their actual meaning.
Any dictionary will toss you a variation of this definition of "cold-blooded" when applied to crime:
Executed without feeling or emotion
Someone yelling "I'm mad! I'm mad!" during a crime doesn't indicate a lack of feeling or emotion and if that same person shows remorse and psychological anguish after the crime, you'd better find yourself another label.
Cold blooded killer = a regular hit man for the mob