Doesn’t matter who started the incident, the main thing is that HK lady kicked the front girls seat . That is rude, she could have ask nicely if she could shift up a little . Plus the girl didn’t do anything wrong, she has the right to move her seat back.
Even tho you can lean back, I don’t do it because leaning back is worst then sitting straight and is bad for your back so uncomfortable. And everyone should have some consideration because you’re not the only one sitting.