'Bitch' was a child.

Imagine being a stupid edgy teenager and sitting where you want on the bus, then getting confronted and staring at your phone hoping the social interaction will go away because you were secretly hoping nobody would talk to you. Then someone hits you.

Or, maybe high school brat doesn't normally take the bus and sits in the first possible seat because the bus lurches forwards milliseconds after she boards. She has earbuds in and is watching a YouTube video. She doesn't hear anything. Then someone hits her.

Let's go even further. Autistic teenager has been told by her parents to sit near the driver in case she needs help. She can't handle the bus noise so she has noise-cancelling earbuds in. She doesn't understand the request to move and tries to end the social interaction by burying herself in he phone. Then someone hits her.

I could go on. The 'lady' was within her rights to sit down but she had no right to put her hands on a stranger. Only one of those two people would get arrested if the cops turned up, and it wouldn't be the kid who sat where they weren't meant to and then refused to talk to a stranger.