The wiki snippet someone else posted explains why back then. They’re sometimes called it today because:
Many people are functionally politically illiterate and still repeat the BS not knowing it’s BS.
There are still nazis running around (sadly far too many) who want to muddy the waters and want naziism to once again don the veil of socialism to appeal to people in category 1 who would otherwise despise the nazi’s true intent.
The wiki snippet someone else posted explains why back then. They’re sometimes called it today because: