It is the middle of a war and the Hussein regime had an incentive to boost figures on the number of Sunnis because they were oppressing the Shia(understatement of the year).
Besides, if you think the Kurds are going to side with Arab Sunnis after Saddam's extermination program you are seriously deluded.
Well in fact Saddam opressed shias just as much as he opressed sunnis and kurds.
Shias hate Saddam because he executed many shia leaders after having bin nearly assasinated by many of them in many occasaions. They hate him because he forbidded a shia ritual of which he found very disturbing, which you cant really blaim him for. We are talking about the hitting ritual where streets are filled with blood, Saddam did not allow that to happend and that made millions of shias angry at him.
But it is incorrect to say that he opressed shias more than sunni's and kurds.
He opressed them all just as much, executed them all just as much and tortured them all just as much, Saddam treated everybody equally even his own family!
Regarding kurds they have the full right to not want to have anything to do with Iraq. Kurds want their own country, they are kurds and they have a history going many thousand years back. They want their own country, Saddam gave them their own lands and he recognized kurds, he gave them more rights than what any other leader of any nation has ever given kurds.
But he wouldnt give Iraq to them, now after Saddam the kurds suddenly got this new opputunity to create a kurdish nation. I respect that but it is wrong of them to just fully give up on arabs and never talk to them again, now when america moves out of Iraq, the kurds will be left alone fighting arabs from south and turks from north. Nor should they ever have just given their souls to america as if america is going to give them the land that they so much want. They betrayed the arabs in order to strenghten their own nation, the iraqi sunnis will hid hard back on them when america is gone. The kurds will save their own lives by supporting the sunni iraqi's, but they dont look at what's on their way they only look at what they have now and want now, a bit childish and stupid sadely.
But lemme repeat for the last time that Saddam did not opress shias more than kurds and sunni's, he opressed them all equally.