According to the video caption, these aren’t just normal citizens but military vets as well. And you can see from the video that tensions are quite high in Seoul with the amount of heavily armed police in the streets.
I can understand why they are so upset, as it wasn’t simply property damage that the North left behind in the wake of it’s shelling the other day. Lives were lost and now the people are angry. They want to know that their country is willing to defend them and that they are no longer in any danger. I know that’s certainly what we would expect from our country.
At some point the boy who cried wolf must be ignored, or in this case, dealt with appropriately. It’s not an easy task considering all who are involved, but it’s clear what the citizens of South Korea want from their government.