Whether we're prepared to admit it or not, seeing our names in the credits file gives us a good feeling. And when it comes to maintaining software, you don't need corporate involvement to have political squabbles. If you have a problem with someone's attitude on the mailing lists or their personality in general, it's likely you're going to be relatively more harsh with their patches, whether consciously or subconsciously. It takes a great deal of effort to retain impartiality when you're dealing with a complete pain in the ass. You can set your own work load, schedules and goals.
Nobody can force the pace of development or release.
Nobody tells you what you have to support, or what features you have to add. You do stuff either because it's cool, because it's needed, or because it's generally the Right Thing. That's the freedom you need to keep. The first one is that, no matter what the conspiracy theorists think, very little dirty dealing actually does go on when companies employ free software hackers. The problem is mainly a matter of perception.