Because there is no cut-off and no focusing of the beam. Light is scattered everywhere and it IS intense. Blinding oncoming drivers. HID headlamps are terrific, and they can offer significant and substantial safety performance advantages over halogen headlamps, but only if they're designed and built as HID headlamps from the start. Installing an "HID kit" in a halogen headlamp isn't an upgrade, it's a large and serious safety downgrade. Halogen headlamps and HID headlamps require very different optics to produce a safe and effective—not to mention legal—beam pattern. How come? Because of the very different characteristics of the two kinds of light source. But, whatever. It's your truck. As long as you "think" it's better, then it must be. To heck with the other drivers on the road.