in this case 'outside' means people like the linux kernel developers who don't work for google or the companies that you have decided that you care about enough to consider 'inside'.
a community is not a collection of people and companies that you (google) decide should be part of the community. A community is those people _plus_ others from outside that group who have enough interest in the project to participate (and participate may be testing, documentation, and even bikeshedding as well as submitting code)
in the case of the android kernel modifications, there is lots of evidence that people are interested in being part of the android community, but google appears to be saying that you are not interested in allowing those people to be part of what you have defined as the android community.