The Realest used it as leverage to get out of his deal with Death Row. The people that told us the information first asked Jon and I not to leak it for fear of retaliation, they were very specific. We have since heard information that was more "vague", and thus posted a reflection of that info.
It happened. People weren't happy. People were silenced. People know about it, it's one of the skeletons in the industry closet.
Also, his voice was altered to make him sound MORE like Tupac, its not like they just took his voice straight out and put it over Pac's, they filtered it. If you listen to the song really closely, in my opinion, you can tell that something is "off" about the vocals.