The crucial part here is the nature of the reputation. We're not talking about some shady dealings of the upper management, that individual employees may or may not have been aware of. We're talking about employee culture inside the company - something that is, by definition, exposed to and shaped by employees. Given the magnitude of the problem in Uber, on the basis of reports we've seen so far, on the balance of probabilities, it would be more surprising than not for an engineer who works there to be unaware that such things are going on around them.

And if they were aware, but didn't blow the whistle (after going through the usual HR complaint process and running into blocks there, as others have reported), that is definitely a very questionable ethical choice that deserves future scrutiny, including for anyone hiring that person.