Some people stand at concerts.
This should not be breaking news.
They stand because they are excited. They stand because the song means something to them. They stand because music has entered their body and asked their knees to participate.
If someone is standing and dancing in their own seat space, facing forward, not blocking an accessibility area, not spilling beer down your leg, and not windmilling like they are fighting bees, they are allowed to enjoy the show.
You may prefer to sit. That is fine. Sit. Rest. Observe. Become one with the cup holder.
But you do not get to turn a live concert into a quiet living room just because your preferred setting is “couch.”
People came to feel something.
Sometimes feeling something has choreography.