Another strategic power play from Trump. He's been toting a diplomatic line which the media and most mainstream political pundits label ill-advised, but it's the same approach he's been taking that's led him get in a position to even have a Korean Peace Summit on the table in the first place. It's the same reason why the American captives were released and why Jong-un shut down his nuclear weapon testing sites. Trump is maintaining his power position over North Korea, and it would be counter-intuitive for him to have gone forth with the summit in-spite of the disrespect directed at his cabinet; and for those who don't know, insults were directed at M. Pence, who, hierarchically, is the U.S.' second in command. What people fail to realize is that Asian politics and diplomacy aren't played the same way they are in western European countries; they're based on strength and respect, not politeness and pleasantry. Jong-Un is not Angela Merkel, he wouldn't get triggered over something like this and virtue signal about feelings.
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You don't deal from a position of subjugation, otherwise you'd be treated like a pushover, which we've seen first hand with Obama every time he tried to gain leeway with China. Trump, on the other hand, received all the stops when he visited China; red carpet, having Jinping come on to the tarmac to greet Trump, etc. He was even given leeway over North Korea in terms of Chinese exports. It's obvious the summit isn't being "canceled", but postpone; possibly by several months or so. In doing so, Trump keeps North Korea on their toes while retaining the superiority in their dealings. It's a win-win.
But don't take my word for it, come to your own conclusions. I'd rather think rationally than have the media tell me what conclusions to come to.