I think Lyft tries to avoid directly smearing Uber for a couple reasons: 1) Uber paves the way for them legally by using a lot of Uber VC money to fight regulation and lobby, which helps both companies. 2) Lyft is doing a lot of the same things that Uber is doing, they're just less gross about it, but they still skirt laws and do other things government actors may not like, so it would be a bit of kettle and pot.