Korea- library incident

I'm currently in Korea's National Assembly Library. I sat down in an empty spot in a table for four people. One of the seats was occupied, the seat next to the girl was left with her bag and coat, and both seats across from her were empty. I sat down in one of the seats, slightly moving the book to the middle corner of the desk that was left open. I positioned my cell phone on top of the book, leaving me with wider space for my laptop. I turned my computer on and started browsing. 

After so many minutes, a man showed up, in his mid 40s or 50s, short and with heavy wrinkled eyes, demanding me to move my seat. I told him, in the same straightforwardness, that I will not move. I heard the girl sitting across snorting. I asked him why I should move. He said that he saved the seat by placing a book. "An open book", he said. I was perplexed because 'an open book' does not suffice as someone's personal belonging. It's barely a personal item in a library. 

I simply said, "no". I though he would snort and move away but he demanded even more when the girl joined alliance with the old man. I could not believe what I was hearing. An open book. That's it? That's all it takes for a person to save a seat in Korea? WTF? I know that people cut in line in subways, waiting for bus and I don't say a damn word because it's conceived as a culture for the elderly in the East but in a library? I don't get it. I left Canada because of their feminist policy and now in Korea- the older you are, you get your way everywhere.