It would be much better to have 100 more cars on the road during rush hour, right?
By providing free transportation from SF Google employees are encouraged to live there. Why not live closer to work? It would probably result in a few more cars on the road but a lot of the employees would move closer to Google freeing up apartments for people who actually work at businesses in SF and HAVE to live there. NB: I have no stake in this, I like in Ireland.
This is because in a free market, housing is like any other good. Some people happen to be particularly affected when competition drives up the price of a given good. But it is not for individuals to try to mitigate this effect. The most efficient and fair outcome is for the government to redistribute money, and for the poor to spend their money however they feel is best.
This is not libertarianism, it is basic economic theory that is shared by moderates on the left and right.
So Google has no moral obligation, or indeed any good reason, to discourage their workers from living in SF.