Mahabharatam is an Itihasam.. meaning "Iti ha aasa" "इति हा आस " " such wonderful incidents did happen" (Wonderful does not mean the incident was right or wrong in itself..)..
It is a chronicle.. the incidents have been recorded by the author ( believed to be Vyasa the Krishnadvaipaayana who is also seen as a character in the epic)..
If you read Bharatham without any prejudices or pre-conceived notions, it can be seen that various incidents have been recorded as faithfully as possible keeping in view the huge canvass that had to be covered..
Each character would have said something to justify his own action, but one cannot see or feel that the author or anyone has asked us to accept that some actions are right and some are wrong..
In a report all things would be recorded, as faithfully as possible..
The original text may be treated as the most reliable chronology of events..
The choice to treat any act of commission or omission by any of the characters, be it Krishna, Pandavas, Kauravas and so many others .. is the prerogative of any reader or interpreter who chooses to read the epic with fair intelligence and if possible, with an open mind..
The opinions mouthed by the characters as recorded in the epic need not be accepted as right or wrong.. The things just happened.
And evaluation of virtues or vices contained in any action by a person, even if it is a puranic or Aitihasic character, can vary with the social ethos as well as the personal mental make up of the reader..
Nothing is right or wrong in absolute terms