HID Car Lights – What’s Wrong With the Regulations?

I’ve read in a recent search about HID car lights that they can be legal or not legal. It all depends on how you purchased it. According to the article,
“Some car owners ask if installing HID lights is legal. If a car was installed with an HID conversion kit, then it is legal. If a car owner would like to upgrade his old lights with HID, then they have to follow three conditions for the International regulatory board to authorize its use:
1. The headlamps must be correctly aligned according to the regulations.
2. The vehicle must be adapted with an automatic headlamp leveling system.
3. The car should be fitted with an automatic headlight cleaning system.”
Ok, I know I don’t have enough legal jargon to make sense of every constitution, but what the heck is the reason for this? Why can’t they just make it legal whether or not it was pre-installed by a company or upgraded in an old vehicle? Why can’t they just allow all the colors to be used and legally ban the ones that cause a lot of glare? It’s stupid, it’s confusing, and it doesn’t make sense.
I never thought purchasing HID car lights can be so complicated.