The first comment didn't say they should have spent more time on security, it said they should have spent time creating a system to detect if too many taxis were in one spot.
I think we can all agree that security is valuable and should be prioritized, but spending time worrying about how to stop who is already in your system from sending all the cabs to the wrong place seems like a waste of time.
Hell, IF (big if) the worst thing a hacker could do once they had access YandexTaxi's servers is send a bunch of cabs to the wrong place, you could almost spin that in a positive light. "We spent so much time protecting customer data that all they could do is send our divers to the wrong place".