We must have been watching different videos
Yeah, you probably watched the one that's recorded from the back, and starts with Vance speaking.
There's another video which is recorded facing them, and there it's clear Vance was talking to a journalist, after Trump finished responding to a question.
The sequence of events is:
1) Trump is answering a question from a journalist about negotiation tactics with Putin. He says it's important to get alignment. Claims he could easily call Putin bad names and ratchet up the pressure on Russia ("I can be tough, I can be extremely tough"), but that that would scarcely lead to a deal. Zelensky was making different faces like a school boy the entire time Trump was speaking.
2) Then Vance says he would like to build on the president's answer. Addressing the journalists (this is clear - he faces away from Zelensky), he says it's time to try something different after three years of a president (Biden) that called Putin bad names plenty of times, but also failed to stop the war. He argues that now is the time for diplomacy.
3) Suddenly, Zelensky says: "Can I ask you a question?". Vance says, "Yeah, sure!". Zelensky says, "Yeah?!", and Vance says "Yep!". Zelensky says, "Ok!" and then rolls his eyes, sighs, and begins explaining to Vance as if he was a child that his country was invaded. Until this point, the three men had only been talking to the journalists and never with each other.
4) Then he says, "My country was attacked in 2014, that was Obama. Then came Trump. Then Biden. Now Trump is back again. The war continues - nothing has been done." How is that kind of comment helpful to anyone - haha?
5) Vance interrupts Zelensky and tells him he needs to be thankful instead of relitigating his position in front of the media. Asks Zelensky if he's ever said "thank you" once, since he had arrived that morning.
6) Zelensky says "I've thanked America many times in the past. But I was thanking the entire American people." Clearly the implication is that he has nothing to be thankful for to the Trump administration.
7) This gets Trump really going, and he begins reminding Zelensky that Obama sent him blankets, and Trump was the first to send Javelins.
The rest is a disaster. But what's clear is that Zelensky was definitely the one that started it. Vance was clearly not addressing him, and wasn't even saying anything controversial. His point was that sanctions, weapons, and warlike speeches had failed to significantly alter the trajectory of the war - and it was time to try diplomacy.
Zelensky could have politely ignored all these things that were irritating him, and the meeting would have ended in 5 minutes. It's not like he hasn't heard them before, and not only from Americans but from Orban, Fico, and others. He was very close to being home free, but then right before the final whistle he decides to open his mouth.
The clips which were spread first this morning were very deceptive in how they presented things. They started right on the moment when Vance is already yelling at Zelensky to be thankful, and it seems like he's under attack from the two men at the same time - unable to defend himself.
The reality is that there were 40 totally normal minutes before, and then Zelensky all of a sudden goes off script and essentially makes it seem as though Vance and Trump's plan is idiotic. This is inportant context.