If you have a popular project, though, or even if you have a crappy project but spend most of your time on work and don't have much time for it - it can be very valuable to drive off people who commit worthless wastes of time like stuff that doesn't compile or pass tests. If I only have time to do one commit or code review per night on my personal project, then I those people are a burden. At Linus' level, his personal project because a full time job and one of the most popular OS in the world, but that doesn't mean it is a good idea for him to start being nice to everyone and getting flooded and not being able to get anything accomplished.