Yomc, they didn't really kill themselves. If they did, Pokemon wouldn't be as it is today. No Soulsilver, White, White 2, Black 2, X or Y, you get it. Besides, it's just a story with no real evidence.
XD There is legitimate evidence, but I didn't say there was a HUGE increase. It has evidence, just no CONCLUSIVE evidence. So yeah, listening to it won't kill you. But that is the real reason why they changed it in the other games, because people were scared of the rumor.
Watches 5 seconds: Oh god, this is going to be creepy Watches 1 min: ._. Watches all: Right then, avoid Lavender town in Pixelmon... Anyway, pokemon faint, they don't die. If they DO, how?
They die either by age or they battled waaaay too much OR they were fainted for too long. Wait, that means pokemon you faint in the wild eventually... YEAH NEVER MIND THAT LAST PART!
Old age. Or I guess if they took a big enough hit. Lucario dies in one of the movies, I remember. (Whoops, spoiled, my bad XD) Picture like a hit from three legendaries, perhaps. At the same time. Or maybe a train crash XD