No. Even if the chance of someone excluding ex Uber engineers is extremely high like 50% (which it's not), the Brand name is still valuable since Uber was once one of the hardest places to get into.
Brand name in terms of engineering ability, the interview barometer during the years OP interviewed? Nothing in the press suggests this has changed. (I'd hesitate regarding senior management types more than ground level engineers -- kind of like Zynga tbh with great ground level engineers and PMs, but pretty questionable upper brass)
Zenefits sales guys don't have a problem landing their next sales role, though you might do a sanity check for cultural values just in case.