Caveat: I have no personal expertise in this area but I have watched how stories in the media can be spun. I think there are some facts that we can agree on:

• Six million is a magic number for Jews. It is supposedly the number of Jews who need to die to ensure they is an Israel.
• Some Jewish people arranged for the USA to join WW1 in return for Palestine.
• The Jews world-wide declared a business war on Germany after WW1.
• Some claim that the people who participated in the Versailles Treaty after WW1 had an over-representation of Jews.
• Another claim that may sound familiar, was that the Jews controlled the banks, the media, the porn industry and was causing the visible debauchery in the cities.
• There was hyperinflation in Germany under the Weimar Republic. When the new mark replaced the old one the ratio was ten trillion to one. Imagine if your savings were divided by 10,000,000,000,000.
• Zyklon B, which is cyanide-based, was used for delousing clothing and fumigating various areas to kill lice, fleas, and other pests. All these pests were extant in the labour camps.
• Tens of thousands might die from typhus in any one camp. The disease is spread by lice and fleas.
• The pictures we see of prisoners tend to be from 1945 when the Allies arrived. Many prisoners look emaciated so they were being kept alive and not killed. Food would be a serious issue after the lines of communication were no longer available due to the invasion.
• The famous Auschwitz chimney was built after the end of WW2 by the Russians and was not actually connected to the nearby building.
• Did the camps have crematoria? Yes, but so does my local hospital. As inmates died from disease that was the preferred method of disposing of the bodies.

In summary, Germans had many reasons not to like Jews because they appeared to be behind so much that was hurting them. Diseases will spread quickly in a concentration camp even if measures are in place to minimise the pests that transmit them. Labour camps are a good way to make money. Many people in the US benefitted.

So, dislike of Jews, six million, labour camps, Zyklon B, death, and subsequent cremations all have an alternative explanation from the one we all know.