Sean Spicer already explained that. There is a SKIFF there and it was used for sensitive conversations.
What more is there?
You’re right, and the media makes it out like he was sitting in a restaurant surrounded by random people. My understanding was he dined with the American and Japanese delegation in a private dining room.
This is a non-issue and I’m frankly ashamed and disgusted by Republicans in congress pulling crap like this. They should be there to drive the agenda and execute the mandate they clearly received last November across the country.