I agree; half-wits who listen to rap music often seem to be of sub-par intellect. Half-wits who don't listen to rap music are more or less the same, though.
However, musical preference is certainly the fairest way to judge a person's character and intelligence in general. This is a well-known established fact.
I must say, though, your statement about drug addicts and bringing down society and so forth does seem slightly at odds with your choice of signature.