As for the peace talk itself, what do war games provide? What's so important about them?
Recognize that in the event war breaks out on the Korean peninsula, the US and South Korean militaries, along with whatever other allies they should have on hand, will need to
coordinate - war games provide opportunities to
practice that.
Should war not break out, sure, then they're pointless. But the whole point is that North Korea has been saber-rattling
much more, shelling South Korean islands, sinking South Korean ships...practicing for war against a state that could well try to
conduct a war if it feels like it seems appropriate.
And legitimizing Kim? Really? Because, what, if you don't talk to Kim he just goes away? I presume you would have the same criticism of Obama, then, since he wanted to meet with Kim Jong Un to. And for Jimmy Carter and Bill Clinton since they met with Kim Jong Il. Yeah, they were no longer Presidents but hey, they legitimized Kim, right?
He
wanted to meet Kim Jong Un. But he didn't, because KJU refused to meet the preconditions for a meeting, or even merely having
basic diplomatic relations, just like both Bushes, Bill Clinton, Reagan, etc. Recognize that the US doesn't even have diplomatic relations with North Korea; everything needs to be done through intermediaries (or 'officially' unofficially, such as 'coincidentally' in the (Insert Nation Here) Embassy while both are ostensibly supposed to be meeting those representatives).
As to Clinton and Carter; when they're private citizens, they can do what they like.