Why Do Reporters Keep Describing the Debates as "Testy"?
For the same reason the television announcers at a professional wrestling match describe the bout they are covering as "testy". It's all part of the illusion of a fake competition between two guys who work for the same sponsors, promoters, and owners. On stage in front of an audience, they are "testy", but backstage they are best buddies patting each other on the back for the show they just put on.
I remember watching one of the 2004 debates between Bush and Kerry. Halfway through the debate it got very "testy". Bush said something a bit personal about Kerry and from then on Kerry's whole demeanor changed. Kerry spent the rest of the debate gritting his teeth and scowling at Bush. I honestly thought it was a genuine moment of pure hatred between the two men.
Well, the joke was on me and everybody else watching at home, because at the end of the debate, after the announcer signed off, the credits started to roll, and the camera began to pan away from the stage, both Bush and Kerry came to the center of the stage and happily glad-handed each while cackling like a couple of sly hyenas. The only people who saw it were the relatively small number in the studio where the debate was broadcast, and those at home who kept their eyes glued to the TV while the credits rolled. They put on a successful, convincing "show" and celebrated like a couple of stage actors who just nailed their lines.
Politics is theater, people. Wake up.