Having heard Uber's reps more or less state that the law doesn't apply to them because they don't like it,
The Uber reps are claiming that the laws the cab companies are quoting are wrong. Cab companies want them regulated as taxi services (provably the wrong thing in almost all jurisdictions). Uber wants to be regulated as a hitchhiker service, with a tip. In reality, they should be somewhere in between, a private car service, where the driver doesn't need a medallion, but they should have commercial endorsements for commercial activities.
So Uber's response, is "we'll treat ourselves in the best legal way (hitchhiker service) until proven otherwise." It's a legally sound stance, many larger companies have done the same thing.
Basically, they're skirting around the law and claiming the law doesn't apply because they don't want it to.
They are abiding by the law. Just not the set of laws the cab cartels want them operating under.
They like to couch themselves as an alternative to taxis, but they don't want to be on the same playing field as them.
Hitchhiking is an alternative to taxis, and doesn't have any of the rules around it taxis do.
Think of couch surfing. Paid couch surfing isn't regulated like a hotel. You don't pay the special hotel taxes. None of the hotel regulations apply to taking $20 for someone crashing in a spare bedroom for a night. Uber's point is that if nobody has a problem with that - the hotel cartels aren't spending millions to come after couchsurfing.com or whatever, then why would anyone have a problem with "monetizing" hitchhiking?