This in essence is your problem. You do not want to live with the idea that Germans williningly committed such terrible crimes, but they did. Although the NSDAP did not have the majority, it did have the largest number of votes than any other party. To put the Social Democrats and the Communists together is something you just cannot do. The political parties in Germany did not have a history of working together. Look at the Weimar Republic.
If you cannot hold Germans accountable for WWII and the holocaust, who can you hold accountable? One man? That is ridiculous. By the way, wikipedia is not the best source. It is ok, but it gave you no specific information about resistence in Nazi Germany, because THERE WAS VERY LITTLE. I cited earlier the ONLY known resistence group, 'the Order of the White Rose.' Wikipedia does not tell you about other groups because they simply did not exist.
I know it makes it easier for people to just vent all of their anger on one person, because you just do not want to believe that people as a whole can do such terrible things, but by doing so the lessons of history are lost, and it makes it easier to be repeated.
To get started, you should read Christopher Browning's 'Ordinary Men.' He paints a very clear picture of ordinary Germans joining Police Battalians and the SS in order to, sometimes even jubilantly, murder Jews on the Eastern Front. These were not criminals or psychopaths, but regular Germans. Perhaps they became the latter and the former, but they were not at the beginning.
Seriously, if you blame just one person you really narrow your understanding.
Just like you'd agree Russians are responsible for Stalin's purges right? Or am I wrong about that?
In Germany, if the Communist Party and the Social Democrats were able to get just about 5% percent of the vote, they would have created a governing coalition, and would have passed pretty radical policies. There was already a group in the SDP influencing the platform to make it more radical in order to appeal to Communists. The 1925 SDP platform "called for the transformation of the capitalist system of private ownership of the means of production to social ownership". Probably like in Russia, the Communists would have eventually muscled their way into power, because the SDP would have been in the same position the Mensheviks had in Russia.
So then, Germans were just as much responsible for the fact that a Communist dictatorship could have occurred there as for the fact that a Fascist dictatorship actually did.
The problem wasn't one man. The problem was massive social, economic, and political upheaval, and extreme ideologues being able to take advantage of that upheaval, demagogue, and use dishonest rhetoric to appeal to discontentments. And there were just as extreme views on the left as there were on the right. Leftists might just as well have won, like they did in Russia. Likewise, there were many men and not just Hitler who participated in horrific acts. Times of upheaval bring out people's dark sides and lead them to justify those things. During the Reign of Terror after the French Revolution, not only aristocrats, but prostitutes, and any groups considered immoral, were executed.
The Wikipedia article talks about documented protests in the Catholic church, among leftists, etc., You think those 18% who voted Communist just decided to like Hitler? You think the Catholics who were targeted by him just decided to like him? His political enemies were sent to concentration camps.
"In Germany they came first for the Communists, and I didn't speak up because I wasn't a Communist. Then they came for the Jews, and I didn't speak up because I wasn't a Jew. Then they came for the trade unionists, and I didn't speak up because I wasn't a trade unionist. Then they came for the Catholics, and I didn't speak up because I was a Protestant. Then they came for me, and by that time no one was left to speak up."
-- Martin Niemöller
And yes, there were racial resentments and anti-Semitism existed. But there was always anti-semitism and Germans had lived through hundreds of years without mass murdering Jews, so the question is why it occurred in the 1940s.