The page is clear and concise. It talks about guidelines for the community, as well as as 'YouTube is for the community.'
I wonder if this is the issue: it is 'for' the community.
Where the community is being created is perhaps on other platforms, through 'share':
In that sense, YouTube is an affordance in the building of communities on other internet platforms.
A Google blog like this one, can integrate videos, and offer the building of a community. But this is not a YouTube community