... of less than 0. The drivers revenues are stochastic/unknown/subject to variance while the costs are known. The driver's hope is that with some luck their earnings will be high enough above average to actually make a buck. Uber preys on this hope and is exploiting low-skilled labor in an economy that has continually been hard on the low-skilled segment.
You are obviously dim if you cant conceive an explanation as to why someone would take a job that may net them less than $0.
This could happen for a shift or two, but anyone who is making less than $0 on average over any period of time greater than a few days is going to figure out that it isn't worth it and stop. Especially when the "job" is one that allows you to work when and if you please.