Some people here have a alarmingly rosy view of what a war of conquest is all about. Fact is that racism, and race-based exploitation, are very effective vehicles for justifying conquest. If you try to treat everyone fairly and equally, then you're gonna run into a LOT of problems trying to build your empire. It gets worse if one of the chief reasons for your expansion is to steal resources from others, as was the case with Nazi Germany. Then you need a very good reason why your people deserve other people's stuff more than they do themselves, and racism is very good at providing that reason.
This isn't just talk. People need a reason to lay down their lives for their country, and states that are unable to provide sufficient reason often fold under pressure. Fascist Italy is a good counter example. Although Italy certainly had some of the same racist dogma, it wasn't as pervasive or as popular. Once the going got tough, the Italians asked themselves just what the hell they were dying for, then threw in the towel. A country doesn't fight to the bitter end for nebulous reasons. The Germans fought incredibly hard in WWII because they had a pervasive ideology that made sense to them. That ideology told them they were better than everyone else, deserved to be on top, and were justified in killing anyone else until that became a reality. It was incredibly racist, but as a motivational tool it worked.
With that in mind, there is simply no way Hitler does any of this as it undermines the very war he is trying to wage.