I think the point is they're saying she lifted the hook:
"Hey, (hey) You, (you), I Wanna Be Your Boyfriend" - Rubinoos
"Hey, (hey) You, (you), I Don't Like Your Girlfriend" - Avril
Same rhythm and they both repeat in the first and third lines of the chorus.
I'd bet that there's a small private settlement in their futures. It will be for less than the cost of litigating. If not, the Rubinoos will lose because they won't have deep enough pockets.