Was she happy? And oblivious? Did she say that? Or was she ignoring him to avoid him getting even more obnoxious? What do you think she should have done?
I'm sure she wasn't happy with his behaviour, but she was clearly acting in a way to make it look like she was a fellow annoyed passenger and not with him. She was content to let him inflict himself on the others without saying anything to him (even just a "Come on, Phil - people don't want to hear all that"), but when he reaped a consequence of his actions, she then leapt to his defence and shouted at the men who pushed him out.
I think she should either have tried to settle him/apologise on his behalf for his behaviour OR (my preference) accept that he's a grown man, making his own decisions and dealing on his own with the consequences. Put simply, she wanted to rescue her boyfriend, but didn't seem to care before about the others being rescued from his threatening behaviour.
In a way, she reminds me of the woman some years ago in the USA, who successfully sued a store because they didn't prevent her from being harassed by a small child who was constantly getting in her way and disrupting her, stopping her from being able to do her shopping properly - HER OWN CHILD.