You keep making it seem like all the "kooks" in Nazi Germany were confined solely to the SS.
The entire German government/military/bureaucratic apparatus was deeply involved in various atrocities and war crimes from 1939-1945 particularly in the East. Things like the Holocaust, the genocide of over 2.5 million Soviet POWs within 8 months in 1941, the Commissar Order, wiping out whole villages suspected of assisting partisans, the policy of 100 civilians killed for every German death, deporting people as slaves, use of millions of slave workers in horrible conditions, mass looting, mass confiscations of foodstuffs from the local population etc were all horrific things that couldn't have occurred if it was solely up to the "kooks" in the SS. Everyone involved was guilty to some extent the only thing that varied was how much blood they had on their particular hands.
There were committed/true believer Nazis throughout German society especially among the government, the various ministries and the military. People who had and would have no issue implementing Hitler/the Fuhrer's policies to the letter. These people wouldn't disappear or grow consciences in the event of a total victory. To do so would be going back on the tenets and doctrines of National Socialism to which they adhered to either totally or partially. If they committed or organized atrocities during the war then why wouldn't they continue to do so or support those who are doing it after the war when the REAL work was at hand?
Again, you are talking about the war time, and I am talking about the postwar. We might again draw parallels with the USSR here, as we know that the Red Army did not commit similar bloodletting and atrocities in the early 50s as it did during WWII. I am not saying that it was "only the SS kooks" who were involved in the crimes of Nazi Germany during the war (even if they were the most prominent among German war criminals), what I am saying that they would be chief among those who would argue for keeping up the extermination policies after the war while the "moderate" groups in the Nazi/German power structure would find different priorities in the postwar period (rebuilding the German cities, restarting trade, cooperation with various allied/satellite states to control the occupied areas, various building projects on national and continental scale, defence against the US and its allies, etc, etc). For most of the Germans, the postwar would be different to total war. For every W-SS and Einsatzgruppen member and concentration camp guard, there were many men who served in Heer units or worked on the home front who took no part in war crimes or were only peripherally involved, to give an example. Many men who would serve the Nazi empire in the 50s and 60s did not even fight in the war, being too young for that at the time. And, to be sure, many people who did take part in atrocities during the war would regret that and not want part in more of the same. This is human nature.
The extermination of the lesser races would be the main goal of the most committed believers in the Nazi ideology. But the question is, to me, how big part of the German population would be committed to this ideology after the war, to the exclusion of other, more human and more mundane goals? Most would pay lip service to the tenets of Nazism, sure. But how many would be true believers ready to keep the extermination going or to go East and gleefully fulfill the horrid quotas of a Generalplan Ost? I don't believe it would be as big a part of the population as you seem to believe.
The problem is, though, that this is pretty much up to what I believe and what you believe. As we are talking hypotheticals here, it is pretty hard to say which one (if either) might be right.