Not surprising about the mulleted muppet (rod - I never much liked his music anyway). The bowie thing was usually explained away as him being in his 'Thin White Duke' phase (along with hitler salutes etc), plus too much cocaine (it never turned me into a nazi though, LARPing or not).
I'm not sure, there were maybe signs before - eg in hunky dory, there are a few lyrics that could mean something in the context (eg 'let me make it plain, gotta make way for the homo superior') - not to say that an interest in Nietzsche (or more like his sister's interpretations/selections) means you're a fascist, but together with the later statements, maybe it means something (or not) - he at least denounced the nazi bits fulsomely later on. I still love some of the music on hunky dory, and lots of his other stuff nonetheless, though the credit must be shared with the people he worked with (eg rick Wakeman, Adrian belew etc).