Oh, many of the scientific and tech programs that Hitler initiated were positive. The Autobahn, for example, is how a highway system should be. I heard somewhere that the German government spends something like 3/4 of a million dollars per mile for maintenance purposes. The Interstate system here in the states, by contrast, is a joke and is in poorer condition in many areas than the byways it was supposed to replace.
However, the good things Hitler did cannot be divorced from the fact that he and his pogroms against the Jews, and indeed anyone who opposed him, rank as the single most horrific atrocity of the last several hundred years of human history at least.
