I can't say I'm surprised by the reaction here.
I do want to say that I hope the MJ fan community don't ruin future potentially good projects with their 'purist' views. It's too limited IMO. The MJ Estate have no more new MJ material being recorded so they have to work with what they've got and they are largely unfinished tracks. They need to make money, that is their job.
STTR was almost releasable IMO, all it needed was a fresh mix and the MJ Estate could have released it as a Michael Jackson single, which would have been awesome. A guest artist could have been acceptable, but they have turned this into 'Bieber feat. Jackson' rather than 'Jackson feat. Bieber' which is a shame. While I would have preferred less Bieber and more Jackson on this particular track we all have to accept that guest artists will be in the future and we (as a fan community) need to be less hostile toward projects like this. I would like to see MJ at the top of the album and singles charts on his own, but that is incredibly unlikely. If mixes with guest artists can do it then I'll be happy. The purists can be catered for later with more raw MJ demos and outtakes on album packages. Hit singles need to be contemporary, and they need to be polished. This new version of STTR is both.