One of the issues is that London in that time was very far from "full of native Brits". The 60% he mentions were mostly not seen in the streets when I visited first in 1997, mostly because they lived in the suburbs.
There is nothing at all brave or heterodox or anything positive at all in supporting violent criminal fascists like Robinson. Yes, it is wrong.
Heterodox opinion in some circles, but this is not some fringe belief.