The Trump hate on this forum is ridiculous....some of you need help. This meeting could be a great thing and stabilize a potentially horrible situation. It would be a win for everyone, regardless of who was president.
I'm going to assume that you're relatively young and that this is your first real go around with North Korea, as, while the magnitude of the events that are occurring are unusual, there's nothing so far that indicates that this isn't par for the course to how they operate.
Since the Korean War, North Korea has had decades of saver rattling and then making 'concessions' in exchange for sanctions being lifted and/or aid.
The difference this time would be the degree of this particular theatre under Un, as well as China applying greater pressure, but your sentiment has been exploited for generations as North Korea has never, yet, acted in good faith.
'Kim is committed to complete denuclearization', why? After having just essentially achieved the nuclear goal that was key to the countries long term survival via deteremce, why would they say this now?
Maybe it's because there's a lunatic in the whitehouse (NK has had secret back channels with the CIA since Trump got elected to try and understand him better, FYI) and them having nukes is actually more dangerous in the short term.
So the likely calculus becomes 'pretend to show willingness to meet every demand, getting massive (immediate!) wins on sanctions/trade/PR from the US, SK, and China and run out the clock on Trump since actually agreeing on anything, let alone full implementation, will take years'.
Trump is gone, NK walks back terms after getting 'hung up' on a term of the deal that they had previously agreed to, and even if China reinstitutes their own sanctions, NK has nukes (secretly stored away or the knowledge of how to make them quickly) and is in an overall much better position than they used to be.
It's possible that Kim has killed enough rivals that he is on actual control, and maybe he has said 'I don't want to play this game until I'm dead like dad and grandpa', but you're talking about the guy who had his own family members assassinated, there are no safe bets even if his actions were caused by the machine and culture he inherented.
Maybe China has decided that the age of direct warfare has come to an end so much that they no longer need to direct deterrent in Korea as the US crumbles, it's possible but there are so many unknowns at the moment that no development in this current scenario 'turns back the doomsday clock' until it has been proven for years afterwards to not be a part of the same cycle.
This is the answer to "Because I'm excited that we might be a step closer to restoring peace in a region of the world?". Let that sink in. One of the saddest things I've read in a long time
You entwined Trump cheerleading to the still very shaky development that's why people are giving you the side eye. Trump is not a rational actor, so being excited about this is premature, especially given the history.