There are several possible points to be made that would support such a thesis. I'll address them separately:
1) Resources and Manpower - To organize and carry out the murder of 11 million people took a gigantic amount of physical resources in terms of energy, transportation and manpower. All of those resources were thus tied down and withheld from the war effort. The Holocaust involved several hundred thousand soldiers, clerks and guards working in over 1200 camps and ghettos.
2) Jewish scientists - Germany led the world in nuclear physics in the 1920s and 30s, and a number of the most prominent scientists were also Jewish. Once Hitler took power and began a program to weaponize the atom, many of these scientists left the country or were smuggled out (Albert Einstein among them), ending up in Britain and the United States where they then aided the Allied bomb program instead. By denying Hitler his chance at the atom bomb, the Holocaust also denied him victory
It should also be said that the prisoners in concentration camps manufactured immense amounts of war materiel with no labor cost to the German government. In addition, the confiscated wealth and property of those Jews sent to the camps and ghettos also reaped the Third Reich a tidy profit. So it is equally possible to argue the opposite thesis, that, tragically and horribly, the Germans actually were aided in the war effort by their huge pool of slave labor.