While nobody in hiphop was ever so committed to the truth that somebody rapping about dealing drugs could be convicted on the basis of their lyrics, there's a long history of rappers policing each other's authenticity in terms of things like claiming to be a gang member when they weren't; and authenticity to the art form, in terms of not moderating lyrics in search of radio airplay and commercial appeal.

Of course, these matters are complicated because there are other dynamics at work too. There are some fairly nuanced distinctions - a lot of gangster rappers didn't see Will Smith's family-friendly rap as selling out because he'd never claimed to be a gangster. Among rappers a less well known performer can gain a lot of publicity from starting a feud with someone well known, so some of the criticism has mixed motives (accusing the successful of selling out is a classic choice). And if you believe all financial success is inherently inauthentic, hiphop's bragging and bling celebrating financial success might seem like an embrace of inauthenticity - but I think most such performers would say they were poor and they're now rich and that's the reality they're authentically representing.

However, it's certainly not true to say that hiphop has wholeheartedly embraces selling out, or did so from the start.