It surely can't be legal incompetence -- a large company like this has lawyers to review these things, and who know the contracts they've created.
But it's hard to imagine Uber/Lyft thinking they're going to get away with it -- obviously it's going to eventually turn into a legal suit and they're going to lose.
I really don't get it. Often these kinds of situations happen when the law is ambiguous or unclear, and the company it taking a calculated risk that the courts would rule in their favor. But this doesn't seem to be that, unless I'm missing something?