That is possibly the most inaccurate description of how gravitational collapse works I have read.
Firstly, not only Wolf-Rayet stars fuse heavier elements; all stars do it as they approach the end of their lives.
This has nothing to do with "wielding more gravity" but is a consequence of the energy output from hydrogen fusion no longer being sufficient to overcome the gravitation attraction of the matter in the star, at which point, it can contract sufficiently for helium fusion to begin, until the helium is all gone, etc., all the way up to iron. Once you get to iron, nuclear fusion no longer releases more energy than it takes, and fusion stops. Gravitational attraction takes over.
Therefore, stars end their lives in one of two ways; they do not have enough mass to continue fusion of heavier elements, and they essentially 'go out', or they collapse in on themselves and explode in a supernova.
Secondly, The Pauli Exclusion Principle applies not only to electrons but to all particles. This is, however, a moot point, as this paragraph appears to be describing how black holes form (which may or may not happen in a supernova), not the mechanism by which supernovae occur, which is essentially a collapse and rebound, with a not insignificant part played by the shock-wave generated, which is thought to be the mechanism responsible for the nucleosynthesis of all elements heavier than iron.