Trix Farrar:

Git is not version control! It is a means with which file trees are to be kept in sync. The fact that it allows mutable history invalidates it as “version control”.

It reminds me of Poul-Henning Kamp’s comments, as quoted on Makefile.feld:

Git is a tool which allows people and projects to manage, modify, fork and merge the many different views, instances, variations and modifications of a work in progress across barriers of distrust.

The crucial word there was “many different”, which is the exact opposite of what a VCS strives for.

A lot of the features Git provides, features which are what makes it great as a colaboration tool, flies in the face or or directly invalidates the guarantees you normally expect from a VCS, most notably progression of time & version, immutability and consistency of view.