*the Nazis were left wing socialists*
Nazis had socialism in the name, Hitler openly despised marxism and framed it as a jewish tool. Also in nazi propaganda social was literally redefined to be national. So the answer to "is nazism socialism" is "yes, if you redefine socialism to be completely opposite"

*voted in by socialists*
That is directly lie, socialists at the time were busy voting for DSP - German Social Party. Hitler's base were reactionaries angry with Gernamy's treatment after treaty in Weimar. You know, reactionary, as in fringe conservatives combined in this case with nationalism.

On the other hand, first antifa movement in Weimar Republic Antifaschistische Aktion was formed by socialists and communists in opposition to Hitler. So it shouldn't be a surprise that the first concentration camp - Dachau, was formed for communists and socialists, including social democrats.

And you might have heard of night of long knives, an event in which nazis got rid off actual socialist wing in their party leaving it purely reactionary and nationalist.

*play the exact same identity politics as the modern left*
You mean persecution of minorities? In case of nazis jewish community? With conspiracies framing them as a scapegoat? Sounds more like modern altright advocating for ethnostate via removal of blacks, you know, like literally Lebensraum? This is opposite to what's left doing.

As for video: good thing you give us 24seconds video and not full context of who that old lady is. After all, old people are completely impossible to be nazis, right?

The only indication that antifa are fscists tat can be concluded from this video is that they use violence, which poses as a problem - violence isn't a sufficient characteristic to tell the difference between fascists and nonfascists for 2 reasons:

1) EVERY political ideology uses violence, by your standards it'd mean that all systems are fascistic. In reality the difference is against whom violence is used - fascists such as Hitler used it against minorities - racial, ethnic and sexual. Antifa use violence against people directing harm on racial, ethnic and sexual minorities. Those 2 are simply not comparable and if you insist on saying that it's fascistic in same sense, despite being explicitly told the difference then frankly don't be surprised that people think you argue in bad faith.

2) According to your criteria, coalition against Hitler during WW2 is fascistic. THEY USED VIOLENCE.

Not having knowledge is 1 thing, this could be ignorance, and if you sticked to the video the only nitpick I'd have is that 24s video doesn't tell us much and certainly not the whole story.

But for some reason you decided that sharing nazi propaganda (Hitler redefining himself as a socialist) is good idea. Not to mention blunt lies such as "socialists were his base". You can have lacking knowledge in good faith but it takes malice to share 80 years old propaganda of a fascist and simply historically false statements. That's how I determine whether someone argues in good faith.