Pragmatism vs Idealism
Thank goodness for Linus. He produced an functioning kernel in rapid time and provided the impetus for people to improve and expand on it - new architectures, networking, file systems etc. This is pragmatism in action.
And the reason he did this was because he was annoyed by the glacial pace of development in the Hurd project. Hurd was all politics and doing things "right" which may explain why 29 years later Hurd still hasn't seen a 1.0 release.