It's not a "bus line". It's a point to point service that causes parts of SF to become artificially more desirable to Google employees than they would be otherwise, whose wealth is propped up by Wall Street investment patterns.
This causes those particular neighborhoods to have housing costs move out-of-reach of median incomes.
I disagree with your use of the word "artificially" as every human construction can be called artifice. There exists sufficient mass transit in SF that SF Googlers can take MUNI to the Google bus stop from wherever they live in the city. The bus didn't cause all the Googlers to move to SF and take over the neighborhood; the Googlers were already living there and driving / carpooling / vanpooling to Mountain View in some number of vehicles that exceeded the number of buses now on the road. Every driver should be cheering. Yes, the bus means that some Googlers will decide to move to SF. No, you can't always have everything you want, not as long as others have the freedom to do what they want. Change happens. It's time for cooler heads to prevail, and for the neighbors to get to know the Googlers, invite them to integrate as a part of the awesome San Francisco community, tutor some inner-city kids, encourage them to use their 20% toward solving some local challenges, and embrace the future. Because San Francisco used to be so good at that.