It's just that human beings take formality so seriously(let's "get married"-it's just a peice of paper damnit!Read the signature below)they have to come up with standards for everything.
And we happen to be obsessed with "science".Especially those of us that don't consider ourselves scientists.So much so that even though we don't really agree to the accuracy or thoroughness(if there's such a word)of these tests as a measure of our person,we wen't ahead and did them.It's so easy to sell any crap that has been "scientifically proven" to be....(It's so hard to argue with that statement).
IQ things are,I think,a bit like horoscopes.I don't really believe in them.But I'm always reading them.
*shrug*