Companies are trying to save money and increase innovation by integrating third party code, including free open sourcecode, into their software supply chain.
The notion that freecode should beget more freecode is central to the open-source movement, but it's a sticky point to companies, like Cisco Systems, that make a living off of intellectual property.
Because Google offers Android for free, including the sourcecode, it makes Google look like a saint, or a company of higher moral standard than Apple or Microsoft.