I've been to Menlo Park. There are homeless people there. Facebook employs janitors and cafeteria workers as well as engineers. Affordable housing makes sense.

But the real problem with building in Menlo Park isn't your concern for poor people living there. It's the "village feel" attitude of the zoning commission, who won't let anything substantially larger than a single-family house be built there. In particular, Menlo Park is highly resistant to building vertically - the best way to get more units onto limited land.