Regarding the airplane incident, isn't Korean Air more at fault than Park Soo-hong? Why is all the focus on Park Soo-hong?

Korean Air could have simply informed him that once he disembarked, he wouldn't be allowed to board again.
If they had just firmly told him "no" when Park Soo-hong said he wanted to get back on, wouldn't that have been the end of it?
It's not like Park Soo-hong is some powerful person.
If he had caused a scene when trying to get back on, that would be one thing,
but didn't he board only because Korean Air allowed him to when he asked if he could get back on?