So, is WordPress a community project, or is it Matt's baby?

We can't have it both ways.

The primary reason that I changed the "Other WordPress News" feed url from planet.wordpress to Ozh's Planet WordPress is that Ozh's feed generally has more useful posts/information. So, I agree wholeheartedly that the Planet feed would benefit from having non-WP specific posts culled.

Posts about Matt's trips to Paris (or any other non-WP posts from anyone else on the planet) do constitute spam in the context of the WP admin dashboard.