It's all very hard to say.
I agree, watching Kate completely ignore Jon at the party was probably one of the coldest things I have ever witnessed on tv. Her smile when she knew she was ignoring him kinda bugged me.
I know many people don't like her, and I admit that sometimes I think she has gone a bit too far, but I don't think she's THAT mean... I mean, They showed videos of when they were dating and such and she was so much more carefree; I think the multiples made her so structured and more forceful when she talks, for lack of a better word. My cousin, who is one of the nicest people ever has two kids, one with Autism, and she talks to her husband many times like Kate does to Jon. Not saying it's right, just bringing up that not many people can complain about all of Kate's behavior if they don't have 8 kids themselves.
It's all hard to explain, I just think she doesn't mean to come off that way all the time, but HAD to sometimes to just get things done! Plus, she's just a more forceful personality.
All that said, who didn't melt when Hannah (?) say her friend Brayden come to the party. The way she cooed his name and did that little shuffle-step towards him. And then Jon's reaction at her inviting a boy, hehe.