I think there have been tons of negatives about Kate..way more than Jon. The biggest difference IMO between the two, is who says what about them. For Kate, it's generally (other than Kevin and Jodi, who had their own axe to grind when they weren't going to be paid to be on the show, and according to Jon they got paid) someone that has barely had anything to do with her, a neighbor that she slighted, an unnamed source, someone who worked with her, but no name is mentioned, etc. With Jon, it's often someone he's been seen with having lunch, hanging around with, had a so called affair. I think that is why his 15 minuters are more abt to be believed. There is usually some grain of truth. We know that Kate 2 was with him, we just don't really know if she was 'with' him. Same with Stephanie, and the school teacher.
What do we have with Steve? Pictures of him escorting her, but not out in bars. Pictures of his wife with her 'good friend' Kate. So which tabloid stories are more believable?