This is a particularly disgusting instance of Germanophobia. I guess that tens of millions of people use the German language every day makes you uncomfortable, as well?
There are some German terms that have taken on a particularly distinctive significance in terms of the Nazi era, like Lebensraum, Endlösung, ausrotten, Anschluss, even if they have a more generic literal meaning. (That's true of terms in other languages that have a strong connection to other historical events too.)
I don't find that the preposition über has such an association for me -- maybe because I've used it in day-to-day contexts when speaking German as a foreign language, like "nach Hamburg über Zürich fliegen" -- but someone upthread pointed out that it may remind some people of Nietzsche's Übermensch, an idea that the Nazis associated with their concept of the Herrenvolk.
It's possible for some people to perceive a connotation that others don't perceive at all. I was working with some Brazilians on a document that used the term "solução final" as a non-Nazi reference, to mean something like 'definitive solution' or 'complete solution'. I strongly urged them to change the term to avoid the unintended Holocaust reference, but they assured me that Brazilians in their circles used that term completely neutrally, and that readers wouldn't take any reference to the Holocaust at all.
There are certain words (particularly Führer on its own) and phrases that modern Germans avoid due to Nazi associations, but Anschluss is absolutely not one of them. It's a common, general term.
Nor is "ausrotten", at least not in its literal meaning. I'm not sure about how appropriate its use for the figurative meaning is, but its connotations are pretty violent regardless of its Nazi use.
