The whole "chosen of God" business is silly for me anyhow, but the fact remains that Hitler's hatred of Jews was based on his wacky religious beliefs (he did seem to think he was on a mission from God) and conviction that Aryans/Germans are superior in every way and should rule all others.
They also made a convenient scapegoat to get Germans to unite behind him.
When the Nazi party first formed and Hitler first started speaking in public, no one really listened to them or took them seriously. When they started saying all of Germany's problems were the fault of the Jews (and others), people started listening to him. When he started declaring his intention to do something about the "Jewish problem" (and others), people started backing him.
Also, it wasn't mainly religious grounds. Not the main reason given, anyway. That was old-fashioned and superstitious. The Germans were far too advanced, intelligent, and enlightened to hate people over something as petty as religious differences. It was a matter of scientifically-based race research that "objectively" said that Aryans were the master race and all other races were not only as good as a separate species, but genetically inferior. Based on science and reason. Because they were so sophisticated and enlightened. [/sarcasm]
Not quite, his hatred of the Jews was more than just a religious thing. Actually, a lot of blacks are angry at them too for what they see as stolen history/culture. There were, believe it or not, actually people of color within the Nazi army for similar reasons. Hitler used that and other things to try and get people to hate the Jews.
Not all religious and not all inaccurate, even if he was still evil and simply used this to unify Germans under him against a common enemy as they saw it. It was convenient for blaming their woes on and riling up his people. That's the main motivation, and it worked.
No, people already hated the Jews. That's what a lot of people forget. Anti-Semitism was already rampent in Europe long before Hitler even took power (and some areas pre-emptively started exterminating the Jews after Germany's "Final Solution" started taking place but before Germany even got to them, like Ukraine). All he had to do was fan the flames that were already there to spread a wildfire over Europe. That's not to say that everyone already saw the Jews as subhuman vermin or society-sucking leeches (as his party's propaganda certainly helped), and that's not to say everyone supported what they were doing (there were certainly a lot of people who spoke out or hid Jews in their homes), but still... Fact is, Hitler couldn't have amassed so much support or done what he did if there wasn't already so much anti-Semetism.
Still, forcing Jews out of their homes and confiscating all their worldly goods and then systematically murdering them so "good Aryan" German citizens could move into their homes and amass their wealth without having millions of pesky human beings still around to take up homes or jobs or food or air meant for "desirable" folk, could also be a motivating factor in the genocide. (In the end, it's all about money.)
And making the basis of discrimination on Jews "scientifically-based" rather than ideologically-based (i.e. "You're a genetically different race" rather than "You have different beliefs"), also fixed it so the Jews couldn't have gotten out of it by converting to Christianity the way many could during the Crusades and the Spanish Inquisition.