I believe the lyrics is (some) rap songs are negative.
However in my opinion it's the "image" of the rapper's lifestyle and not their lyrics which has the larger impact on listeners .
Both Rap and Rock & Roll lifestyles which include drugs, groupies, sexual promiscuity, and run ins with the law are not what most parents would want their children to emulate.
Young listeners have always wanted to dress, look, and behave like their idols going back to Elvis, The Beatles, The Stones, Punk, Heavy Metal, Jackson 5 or whomever else they were into.
With rappers you see the tats, ear rings, baggy pants following off behinds, oversize jerseys, gold chains, and cocky attitudes that offend those who are not into that genre of music.
Every previous generation feels like the current generation has lost it's mind. However eventually most people do grow up, mature, get a job, marry, have children. and move on with their lives.
The upside to rappers has been in the entrepreneurial arena.
I grew up during the Motown, James Brown, Aretha Franklin, along with many great R&B singing groups of the era. In my opinion they all had much more talent than P.Diddy, Dr. Dre, and Jay-Z. However it can't be denied these rappers whose net worth fall in ranges of $500M up towards a $1B each have far surpassed the performers of previous generations when it comes to business savvy.
They have diversified investments in clothing lines, jewelry, restaurants, nightclubs, alcohol beverages, movie productions, sports team ownership partners, and Dr. Dre sold his Beats Audio to Apple for $3B!
During May of 2013, Dr. Dre and Jimmy Iovine donated a $70 million endowment to the University of Southern California. (Not bad).
If the youth can learn some business acumen from these majorly successful rappers that would be one upside to the rappers lifestyle.