Disclaimer: I own nothing. All Glee characters; whoever wrote them up owns them.
He doesn't get angry because that girl is Rachel.
He couldn't care less about her; she's annoying and he never thinks about what she feels.
If anything, he thinks she deserves it.
No, he gets angry because that girl could have easily been Quinn.
The girl in the carpark being egged could have had blonde hair and blue-green eyes, instead of brown.
Pregnant, instead of not.
And he knows that her being pregnant wouldn't have stopped them.
So he sets out to destroy them, before they get to her.
Because he cares about her.
.
.
.
AN:
Review your thoughts and opinions.