The thing is, you have to understand how just how bad the conditions were in Germany after the signing of the Treaty of Versailles.
Germany had to pay massive, massive reparations to Great Britain, the USA and France. France took away a lot of land from Germany and the Allies took away Germany's colonies.
I suggest you read this:
http://en.wikipedia.org/wiki/Treaty_of_Versailles#Impositions_on_Germany
The bottom line is, if there is no money in the country, the country is in ruin, you have a lack of resources and the overall the reception to all of these ludicrous concessions that Germany had to make, would you not want to put someone in power who would promise to change all that? I would, whole-heartedly.
To put it into perspective:
The total sum of war reparations demanded from Germany?around 226 billion Reichsmarks?was decided by an Inter-Allied Reparations Commission. In 1921, it was reduced to 132 billion Reichsmarks (then $31.4 billion, or £6.6 billion).
A German author has expressed the view that Germany would not finish paying off its World War I reparations until 2020.
Thats more than what Great Britain owed for the Lend Lease Act, which I believe was just over 1 billion pounds (I could be wrong). We (Britain) only just paid that off in 2006.
I personally don't condone the actions of the holocaust or the mass killings then went on to secure Hitler's power, but rather the reason as to why that madman was put in power in the first place.