I don't know Justin personally, but I hope he sets the record straight by addressing the allegations made against him in the petition. Given the source of the complaints, I suspect that there may be another version to this story. I've heard bits and pieces from others but not from Justin, at least not organized in one place. I think having something like that would be helpful.
I do find it worth noting that many of the same people who have loudly protested that people are trying to ruin their careers, demonize them, and the like seem to be part of the effort to do the same to Justin. Perhaps there is a lesson in here somewhere.