I like a lot of trashy TV, but JK always made me feel so physically dirty if ever I saw a minute or two of it.
It might have started with the noblest of virtues in the beginning (no idea: I never saw it in its very early days), but it quickly followed the same ante-upping as Big Brother and various others. They start off with ordinary people, then go for highly-strung ordinary people, then eccentrics, then absolute weirdos and finally, people who are truly broken.
I think a lot of the people on it had a good idea that it was 'confrontational', and knew that they would need to play the game, but underestimated their power to avoid being swept into the machine. Many probably did think that it was just them, JK and Graham, and had no concept of the massive production team actively looking to exploit them in any way possible.
As has been said, many of the people seemed to have learning difficulties - whether diagnosed or not - and without funds, for most of them, it was their only way of getting a DNA test or polygraph test. Where MC people on MN will advise to 'get a shit-hot lawyer', the underclass (and I don't mean that in an unkind way) went on JK, as they saw no other option open to them.
As I say, I do like a lot of rubbishy telly, and I hold my hands up to say that I really loved the Kilroy show. Nothing wrong with confrontation among people with equal power, ability (and opportunity) to put their case - maybe make themselves look a bit foolish; but when you've been deliberately sought out for your lack of any of various privileges, goaded and thrown into the bear pit in front of a savvy team whose job is to destroy you for ratings, that's just putrid.