He was only correct near the end of the video when it came to the radical left making monoliths out of everything.
Trump has explained numerous times what he means by Making America Great Again and it was indeed the competition. He outright said it in his speech where he was announcing his candidacy: "We don't have Victories anymore...." and from certain important standpoints, Trump is right, America has kind of become complacent.
But Jon is wrong about our founding as a country being very multicultural, unless he back pedals and is willing to admit the term white is very broad on a number of ethnic people ("Irish need not apply" is something the left has a hard time remembering). We only became very much multi-ethnic near the end of the nineteenth century and the beginning of the twentieth and even then it was heavily restrictive. And it was those restrictions that allowed the country to prosper because we could focus on more important things, like a crippling depression and two world wars. We didn't have the time to worry about being "accepting" to other people's cultures when they come in; they either assimilated and only brought what would be beneficial to the country or they went back to where they came.
I really hope this reflection is sincere even if it's all for naught. The identity politics will wage on, and while the radical right was significant in helping create it, it's the radical left that intends to keep it alive for eternity.