Kat only cares for people who she can influence, or who she thinks she can influence. She wasn't very "kind and caring" when she was squawking "happy house" at Bex's eviction, when several of Bex's friends were upset. For someone who makes such a big act of being "caring", it was a big slip up and just showed her up for what she really is - an arch manipulator, gameplayer and camera-hungry wannabe. Note how the cookie gimmick makes its appearance whenever she's assured of the cameras being on her. Note how she starts yapping on about people "baking her harr" just before noms.
And Rachel, well, she's just puke-making for her sycophancy towards the Fat Fake. It's such a false friendship, based on nothing but their desperation to get to the final.
