Okay, the “salute” thing is way way off the point (the issue is the coerced personal vote pledge to Trump, not the way people held their arms).
But, defending the “salute” here, the normal way to take an oath where I live is to have your right arm straight out to the side and forearm up, somewhat like what you see Trump doing there in the photo but my parents would have said that is the way an old feeble person or criminally lazy person takes an oath. The top of the arm should go straight out to the side or more up than out. That said, when you are in an auditorium where everyone is standing it is generally impossible to hold that pose without elbowing someone’s nose, so the “oath” gesture tends to be less of a right-angle at the elbow and more of an almost-straight raised right hand. By the time that gesture gets a few rows back, yeah, you’re doing a straight-arm “Hitler salute” type of gesture. Maybe it is a regional type of thing, but I’ve seen this happen in very non-fascist settings in both Massachusetts and California.
Okay, again, the gesture’s similarity to a Nazi salute is completely beside the point, though. What makes this fascistic is the words that Trump led the crowd in reciting, and the admonition he gave afterwards about bad things happening if they break their oath. That is fascist, no matter how you are holding your arms when the oath is taken.
