There's really no reason for Apple not to give more information on their hardware, other than forcing you to forgo a $50 repair in lieu of a $700 motherboard from Apple. So many of this guy's fixes are very simple. Just fixing some contacts with a few pennies' worth of solder.
But because Apple doesn't want anyone to track down these little issues, the whole thing gets shipped to some country with no environmental and labor laws, where noxious gases are released into the environment. This is how Apple became so wealthy, I guess. Good for them.