I think there are plenty of reason for this, and the question should be 'why open source the original code rather than having a clean start without all the depe

I think there are plenty of reason for this, and the question should be 'why open source the original code rather than having a clean start without all the dependencies and ugly things that accumulated over the years?'. Once it's open, people will scrutinize everything, especially something as high profile as parse. They don't need publicity about commit message "Joe is so fucking stupid" that slipped away or something equivalent.