There is a small but vibrant Odinism movement in the UK. There is also a very small, about twenty or so, Odin-worshippers in Grass Valley, California - the Sacramento Bee did a bit of coverage on them a couple years ago. Regardless, if the man entered a "multicultural" room and not a mosque then there was no offense in wearing his shoes. The real offense is that the UK taxpayers are funding a defacto mosque in a Royal Mail facility.
Straight on- if he had gone in there with a mirror to worship himself there would have been no right to abuse him.
He would have been stuipd, however, because he could do the same thing over at the DNC and get paid to do it, but that's beside the point.
Shalom.