I think you are answering your own Question. It's Celebs. They aren't "regular individuals", they're "role-models". Whether they choose to be, or not. When you decide to go into a Profession that's widely seen by the media - you become apart of it, especially if you become famous. (as is the case with 90% of the people you named off)
NO ONE should ever be considered guilty until proven otherwise. Every case needs to be judged and ruled fairly and unbiasedly, but this is America and overall the World. Its not gonna happen that way, because once again they're Celebs. You'll see a higher "crackdown" rate on celebs being punished harder now - then you would've in the past. It's mainly because a lot of celebs these days are of the firm belief that they're above the law.
A strong case in point would be your Micheal Vick case. Or even the situation with O.J Simpson. They broke major laws, and for whatever purpose didn't even hesitate to do so upon the time they broke them. They didn't think what the outcome would be - because they likely just assumed because they were famous, that they could get by with it and the court case would be either blown off - or the situation would just die down and disappear.
Simpson's murder trial really fucked him because ever since that issue, many people still haven't gotten over whether he did or didn't do it. So naturally, when the dip shit does a B&E, it's going to warrant major repercussion. Hardly anyone would've wanted to see a possible murder-er walk on another (slightly) major law issue.
The other thing is, it's the media's job to more or less make every celeb look horrible. Call it the "Wake-up Call" for Celebrates. It helps even them realize they aren't Super-human, untouchable or immortal. Everyone is shown and seen as weak, and in bad situations. Everyone has them, just not everyone (only celebs) get ridiculed for them. Once again - all falling back on the fact of them being role-models to everyone else, because of the publicised Profession they decided to go into.