You're not alone. I thought she was an angry, bitter, nasty bitch looking for laughs by making fun of all fat people. I saw her as a 'mean girl' and didn't think her comments were particularly funny, in fact it was getting uncomfortable. And then Whitney walked in and made it all about herself, as if Kerryn was attacking just her. At that point the mood changed and it suddenly WAS about her specifically, opening the door for a full on fight. In that scenario, Kerryn was clearly more skilled at debate and Whitney was left in the dust.