"I don't think anyone is saying or even implying that using Uber makes it legal."
That's part of my point - people avoid the conversation about the legality and use "I like it" as though it matters.
And yes, using Uber does indeed send a message that this is what the people want, but that does NOT justify, in any way, shape or form, the actions of Uber.
Because I love analogies, let's consider something that has been discussed numerous times in this forum: illegally downloading torrents.
If you use public acceptance of a service as a measure of its legitimacy then downloading movies illegally can be considered one of the most well-supported services of modern times. Maybe if the Pirate Bay and Kick-ass Torrents branded themselves as 'disruptive' things might have gone differently.
YES, the legal offerings from existing players are inadequate. Yes, downloading torrent files provides benefits that are simply not available from legitimate sources. Yes, it is still illegal.
Uber exists because a market exists for such a service and that market, in turn, owes its existence to the complacency of the existing players. Anyone who considers this honestly for a moment will see the correlation with illegal downloading of content via bittorrent.
But, as with Bit Torrent, the public annoyance with the incumbent and acceptance of the alternate system does not confer legality upon it.
I don't think these two things are equivalent but the logic appears to be eerily similar: the people support a service that breaks the law so it should be made legal.