Anton isn't a villian - he's a dick head.
As for him trying to stir it - remember, Jem has the same opinion on Anton as most of the public do - she's seen how backstabbing he is and she told Faye this almost as soon as she arrived in the house.
Also, Faye's expression showed that she found it hard to believe that Harry had said what Anton relayed initially - and both of them at the end of the clip, were doubting what 'everyone' was saying... (which includes Anton).
As for Aaron not sticking up for her...why the hell should he! He's hardly really spoken to Jem - as Jem herself admitted only one day again also.
If Jem's as savvy as she appears to be, once she's digested this info: she recall how sneaky, sly and two faced Anton is - and click on that all he is doing is trying to save his own neck. Jem also saw how Aaron was intelligent enough to hoodwink the wolfpack into changing their nominations....... you can be sure that she and Faye will still stick to Aaron's group. for sure.