Regarding your remark on conservatism: it's true western European conservatives were anti-Semitic but they did so in a rather stately\old fashioned manner they most often just disliked the Jewish nationality or had the old religious arguments (we killed Jesus you see).
You also used to sacrifice Christian children for Pessach whenever you got away with it.
You worshipped the devil and committed unclean acts with swine. It was necessary to lock you in at night and all day sunday (the latter law had to be reaffirmed by the patrician city fathers every dozen years or so because the common people including the city guard just wouldn't keep up the necessary vigilance.) And when the old powers-that-be were resurrected to their old levels of command in 1813 by the Prussians and the Russians, the first thing they did - literally - was to eject the sole Jew hired into the civil service during the Napoleonic years. (He went on to become a famous writer... and be baptized
. Ludwig Börne.)
This kind of thing is what the antisemitism of German romantic conservatism was built upon. Then later, of course, we got the bizarre split among both Conservatives and 'Antisemites' (this is what the media called them; they preferred Deutsch-Sozial and similar terms. The quotation marks are needed because, though certainly Antisemitic, that's not all they were and they were not the only Antisemites around) of whether Jews' defects were largely due to their inferior race or their inferior religion - with immense practical consequences due to the large number of converts among upper-class Jews.)
And when the DNVP proclaimed itself the Only German Party in its early 20s election campaigns, what they meant was that there were DVP MPs of Jewish decent.
Hitler has a long pedigree, and the shock and disappointment is largely due to a long pattern of the the German upperclass publicly hating on you but doing business with you anyways - that German Antisemitism, while widespread, had a worse bark than bite.