Goebbels set a frequency all music is set to now

This refers to what's effectively an urban legend about tuning frequencies. The frequency by which we determine musical notes is arbitrary, to a degree. An A note can be set to 432Hz, 440Hz, or something different. 440Hz is in fact now the ISO standard for concert pitch. The whole "Nazis gave us A440" myth usually says that pre-Nazi music used a more "natural" 432Hz reference pitch for A but that the Nazis introduced 440Hz as the reference pitch and that this is "unnatural" and has a whole of other nefariousness variously associated with it (making us more aggressive, etc).

So this aspect of your question has both an historical component and a music theoretical component. Historically, the Nazis are not responsible for A440; reference pitch for orchestras has varied from one orchestra to the next throughout history and standardizing concert pitch was subject of discussion throughout the 19th and early 20th century, with A440 being a contender long before Nazism came about. Arguments for Nazi involvement seem specious at best (eg, "the 1939 British Standards Institute conference at which the British decided on A440 as a standard was a Nazi plot").

Musicologically, there's a great deal of ink spilled on A432 vs. A440 and the summary is that there's no scientific rationale for choosing A432 over A440 but there are many numerological and pseudo-scientific ones. There's nothing wrong with tuning an instrument or an ensemble to A432, as long as everyone is tuned to the same reference pitch. It will sound different than tuning to A440 but there is no metaphysical significance to that difference. Since this is less of an historical point, I would recommend reviewing some of the threads in /r/musictheory by searching "432" or "440" to learn more about the musicological details.