This is due to political correctness. The recording was illegal. Hulk Hogan had the most obvious expectation of privacy there is. The tape of him was released as revenge porn, and the transcript was leaked against court orders. The guy is a victim of a crime and has repeatedly had his privacy violated. He's not a major public figure anymore, and this isn't, in any real sense, newsworthy.
I don't actually know what Hulk Hogan thinks, or how he treats black people. The willingness of the media to ignore his privacy and the context this happened in is kind of crazy to me. There is a public policy reason not to use these statements against him. We're talking about what is essentially a thought crime (which we only know about through violative and illegal acts.)
I agree here, it's like there is a witchhunt agenda in the media to flushout any act that can be construed as racist by any means possible. It's like the Paula Dean thing, she said the N word 20 YEARS AGO and got strung up for it...
People can and do change, I'm sure we are all a little more PC and open minded today than 8 or 20 years ago.