Jousting CAN hurt horse and rider. I don't know who told you that, but if you paid attention to anything done on tv, you'd have an idea...
I am part of a renaissance reanactment group and help my jousters. The number of times one has been hit in the groin, twisted an arm out of socket, pinched a nerve, FELL, got hit in the head, or even had a horse jump the stage with rider on, is innumerable. It's a dangerous sport and I don't take kindly to someone stating otherwise. Sorry if this sounded harsh, but as a groundscrewman I've seen/heard a lot about stuff that went/goes on. It's not pretty. We try very very hard to make sure no one gets hurt, but horses can't be choreographed and stuff can go awry in a blink of an eye.
The armor CAN help, but is not supposed to be a replacement for safety gear. There was one time our Lead jouster got hit in the head. His pig-face [helm] was what saved him. But if that hit was closer to the tip of the beak, it probably would have folded inward. There have been times where only luck has saved him from his armor causing serious complications.
I have pictures I can add, too, now that I've given my safety schpeal.
We actually require more armor than what is shown here. As of last year, we make our own armor, 18 guage, and are making tasses, gauntlets, pauldrons, gorges, cops when we can get them, and god only knows what else. I'll update with fresher pictures when I can fidn them. Jousting