Those bikes have been depreciated to a specific value and selling or giving them away might contradict that.

I'm sure Uber tried to sell the whole passle off to companies who do this kind of liquidation thing. The fact that Uber had to destroy them tells me that either A) Uber is making a lot more money by pulling the batteries and motors and selling those while cruching the rest or B) nobody wanted to touch them and Uber got stuck doing this themselves.

I suspect Uber got stuck. LiPol batteries are a liability and probably nobody wanted to deal with them.