People see this and then hear the "Trump is Hitler" rhetoric, and they recognize the incongruity.
You make a great point here. Whether at McDonald’s, or that barbershop he visited last week, Trump is very personable and easy going when he’s interacting directly with people.
It’s probably because he grew up hanging around construction sites and interacting with service personnel at his hotels that he’s developed this.
I read also that one of the reasons why a bunch of Generals are pissed at him was that he ignored their Afghanistan advice and sought the input from enlisted servicemen before making a decision. This was at least what Sean Spicer told Meghan Kelley on her show a few days ago.
Trump has a great ability to connect with people, which explains why the media does everything they can to push a different impression on people.
It would have had less of an impact on a national scale if the campaign event had been staged at a generic "Joe's Diner" in the same town.