One way and another this symbol has a long history - at one time it was used by the Chinese Red Cross at tge start of tge cetury.

The swastika in that dance is actually not the one the Nazis used, it's the mirror image, going clockwise, which in Hinduism symbolises wellbeing, whereas the version the Nazis used supymbolises darkness.

I'm not sure if the Nazis picked that version intentionally for that reason (a lot of people seem to find the idea of picking the Dark Side quite appealing) or whether they got it right by accident.
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There were plenty of Latvians who fought against the Nazis. But of course the Russians had only invaded and abolished their country in 1940, so it's not surprising that initially many saw the Germans arriving in 1941 as liberators.