www.uber.com/en-US/legal/usa/terms

And here is the relevant text:

YOU ACKNOWLEDGE THAT UBER DOES NOT PROVIDE TRANSPORTATION OR LOGISTICS SERVICES OR FUNCTION AS A TRANSPORTATION CARRIER. UBER'S SERVICES MAY BE USED BY YOU TO REQUEST AND SCHEDULE TRANSPORTATION OR LOGISTICS SERVICES WITH THIRD PARTY PROVIDERS, BUT YOU AGREE THAT UBER HAS NO RESPONSIBILITY OR LIABILITY TO YOU RELATED TO ANY TRANSPORTATION OR LOGISTICS PROVIDED TO YOU BY THIRD PARTY PROVIDERS THROUGH THE USE OF THE SERVICES OTHER THAN AS EXPRESSLY SET FORTH IN THESE TERMS. UBER DOES NOT GUARANTEE THE SUITABILITY, SAFETY OR ABILITY OF THIRD PARTY PROVIDERS. IT IS SOLELY YOUR RESPONSIBILITY TO DETERMINE IF A THIRD PARTY PROVIDER WILL MEET YOUR NEEDS AND EXPECTATIONS. UBER WILL NOT PARTICIPATE IN DISPUTES BETWEEN YOU AND A THIRD PARTY PROVIDER. BY USING THE SERVICES, YOU ACKNOWLEDGE THAT YOU MAY BE EXPOSED TO SITUATIONS INVOLVING THIRD PARTY PROVIDERS THAT ARE POTENTIALLY UNSAFE, OFFENSIVE, HARMFUL TO MINORS, OR OTHERWISE OBJECTIONABLE, AND THAT USE OF THIRD PARTY PROVIDERS ARRANGED OR SCHEDULED USING THE SERVICES IS AT YOUR OWN RISK AND JUDGMENT. UBER SHALL NOT HAVE ANY LIABILITY ARISING FROM OR IN ANY WAY RELATED TO YOUR TRANSACTIONS OR RELATIONSHIP WITH THIRD PARTY PROVIDERS.

(I added the bold..) 

which now, reading about Rasier, makes sense : this shields them from THAT entity, too.