Clary is back to her status quo of manipulating and using people to get what she wants. She only thought about Simon when she needed something from him. Hell, Clary hasn’t really mentioned or thought about him for at least a few chapters, but now she thinks of him when Clary needs Simon to look something up on the internet for her.
I also have to ask: Why didn’t Clary call Isabelle? Seriously, at the very least she would have someone who she could trust (I’m not counting Luke) at her back, at the most she could have sent the experienced Clave operatives to confront Valentine.
Also, I would like to point out what Simon said about Park Slope. With one sentence he managed to debunk all of that ‘Clary comes from a poor working-class neighborhood‘ bullshit that Cassandra Clare tried to push earlier on in this book. In the end, Cassandra Clare herself revealed that Clary is just one more entitled privileged white girl.