- sabotaging competition, at some point even hiring people to do it and providing them with burner iPhones and credit cards
- threatening journalists
- privacy issues
- tax evasion and the whole contractor vs. employee thing
- (purposefully) basing their business on drivers without proper insurance
- abusive rating system (though here I'm not sure if this isn't simply a good idea with very hard to solve side effects)
There was also a long article posted here few months ago that detailed the way Uber squeezes the money out of the drivers (already locked-in by car loans they were encouraged to take) once they establish their market domination.
And note, I am not denying that the current system is corrupt and barely functioning. I'm happy that it's getting upturned. But we've been doing it in Europe for some years now, and it didn't require anyone to behave like this.
They were trying to sign drivers on competitor services up to Uber. They weren't sabotaging anything and were taking legitimate rides, just promoting Uber while taking them.