Maybe she doesn't realize that WW II is over and that we won.
Plenty of silly young white men are still attracted to Nazism ( I've known a few ) in the same way that plenty of silly young Muslim men are attracted to IS.
The trouble is that there aren't many people left in Europe who can remember WW2 or the misery that nazism caused so it seems heartening that the girl is concerned enough about it to go out & demonstrate.
She looks about the same age as my idiot nieces - all they're interested in is cars, phones & crap television.