Because it may be easier for *you* to just fix it, but it's a pain in the ass for the package maintainer to keep track, the release manager to keep track and the rest of the people who have the problem in the future.
Having CVS committers "just do it" may be worse than having the bug fixes show up in the forums. The reason is that then no one hears about it - when someone comes to the forums asking how to fix something in their code, the answer is inevitable, "this is fixed in HEAD - you can try to upgrade or wait until the next version comes out."
It also freezes out those who contribute fixes but don't get it into CVS because the current committers aren't paying attention to the bug tracker or spending their time "just doing it".
Not to pick on you Janine, but we do need to figure out a way for greater developer transparency. The forums were used well here, but in order for development transparency and scalability to be implemented the process should finished with a short bug report stating that there is a fix for a certain problem relating to a certain version with a short patch.
This may seem like the bureacracy of a large corporate software enviro, but it's not. It's the environment of a medium to large open source software community with many users and developers trying to keep track.
The amount of time that will be saved for everyone will make up for any short inconvenience that the developer may face.
talli