This is a very interesting question you pose and I do have answers.
Firstly: The media and the Hollywood elite mainly consist of people of Jewish heritage. Michael Jackson was not Jewish but a Jehovah's witness. He had disputes with his record label and some big wigs in Hollywood. I don't know if you recall his song 'They don't really care about us' he used some anti-Semitic curses i.e. hate me, kike me, referring to the way the media had destroyed him. This did not go down well, hence his demonisation in the press. Mel Gibson suffered a similar fate with his outburst against Jews, He is effectively exiled. Michael Jackson is just one case, If you recall Priests who abused children over 30 years earlier have been deemed guilty even before the cases have gone to court. The defenders of Polankski are also the same ones wanting Catholic priests' heads on platters, yet at the same time state Polanski's crime happened so long ago it shouldn't matter any more. Others say Priests were repeat offenders and that Polanski only did it once hence it is not the same. But this too is a lie. Polanksi a couple of years after his arrest attested in an interview with a man called Martin Amis ( Am man who is a great fan of 'Nabokov's Lolita' a controversial film about an elderly man having sex with a 12 year old girl) that he liked f--king little girls. Everyone wants to f--k little girls even judges and juries hence the interest in his case. He has had numerous affairs with young girls under the age of 16, a well known one was kinski. It is quite likely that he has had many victims but unlike Michael Jackson's case where the accusers blatantly blackmailed Jackson and were very unsavory proven liars no dirt was thrown on them, however Geimer the victim in Polasnki's case was demonised and vilified, her mother was castigated for allowing her to be with him alone even though the mother had not left her daughter with him alone. Her life was made a misery. The media camped outside her lawn, went to her school and splashed her photos across all the papers. Imagine how that feels? The family had to go to court many times to get any settlement, despite what the papers are saying. If you can imagine this, as a young girl who has been violated would you press charges. New victims are hardly going to come forward. Whereas the Media sought out Jackson's victims.
Polanski is part of the inner sanctum of the Hollywood elite. Many of the people who signed the Petition have made money on the back of his films and now court power as a result. Also, if you recall some of the directors have dealt with the subject matter before i.e. the Director of 'Kids', has graphic scenes in his films where 12 year old girls are shown having sex and unconscious young girls being raped.
Gender is a key element here. Girl rape is seen differently to boy rape. This is a combination of homophobia and what Polanksi admitted to in his interview: the people he hung about with wanted sex with little girls. Most of the power brokers at the top are Powerful men and women who try to latch on to them. Hence, the response is unsurprising.
Recently in England a well known personality Jonathen King was sentenced to 6 years imprisonment for sex with young boys. The evidence was quite scarce. Most of the boys had been 16 or over, only one had been 14, all of them came back regularly for more assaults. They have been compensated and are commiserated with; their pictures were not in the papers they were protected and no mud was thrown at them. The offenses took place more than 35 years earlier, when sex to a boy under 21 was illegal. No-one I mean no-one defended him or made excuses for him even though these boys were not drugged.
The treatment dished out also shows how the elite are viewed.
Michael Jackson's case was littered with legal inappropriateness and some elements of the proceedings were downright illegal, but no-one in the media sought ask for his case to be thowne out. The BBC (UK taxpayers money used) co-produced a documentary for the defense of Polanski called 'Wanted and Desired' in this documentary it was confirmed that the Judge was going to renege on a plea bargain and give Polanski more time in jail. Hence, his flight to Europe to escape justice. The Prosecutor now claims that the documentary maker wanted to show just cause for his flight from justice so this fabrication was made up especially as the Judge was dead and couldn't defend himself. He has nowmcome forward and said everything he had said in the interview was lies and he only said them was due to pressure (by the filmamker) and a promise that the video wouldn't be shown outside France. In Polanski's case they had to make up legal misbehavior. In fact the reason the case was re-opened was directly as a result of his defense attorney forwarded this documentary to the United States trying to quash the case. Polanski started to believe his own hy