All these conferences remind me of a parent trying to get their child (who has learned to lie) to tell the complete truth about what happened. The child of course, just spins the web and creates more lies, until they run out of them, or they realize the parent isn't going to give up or give in.
Now while Trump is trying to do the right thing, the problem is that he is scolding other adults, who won't give up easily like a child will, and the only chance Trump has of getting anywhere with the media is to continue this campaign for truth, for a very long time. Which may prove futile, regardless.
The other problem Trump has is that some people don't like to see this (mostly dems), because their used to, or expect, the President to act like royalty and not a normal everyday human being. They want him to act like a sophisticated big shot and show the world how great America is by using big words and talking tough to other countries, while keeping everything else about America's faults out of the spotlight.
I also don't think Trump is 100% right or always honest, but the way he acts strikes me as if Trump knows if he's completely honest, that the media will eat him alive, even if he is doing the right thing. So he simply does what they do. He lies and spins the truth sometimes, which works in his favor, because it makes it much harder for the media to make him look bad. He's basically telling the media that if they wanna play the game this way, he's going to make it as difficult as possible for them. Almost every pitch will be inside or outside the zone, rarely up the middle, and he'll walk the batters he needs to, one after another, all night long. However, If they want to go back to playing by the official rules, than lets play ball.