Longest PoW being the main chain was not described in the context of contentious changes to consensus code. By that definition, a 51% attack that censors transactions would be the longest PoW and be defined as 'Bitcoin'. The great thing about Bitcoin is that the users are able to each make their own decision on what Bitcoin is. Bitcoin needs to be anti fragile and will constantly be under these attacks, because if it fails, we need something better.

This is all new territory and the appeal to authority by citing the white paper is less helpful than most people believe.