On the face of it the only reason he was denied service was because of his beliefs, and the perception many people have - maybe rightly - that he is racist. I can see no other explanation that has been hinted at let alone stated.
On the face of it I think that there is a very good chance he was illegally discriminated against.
I also think that if he was discriminated against for his beliefs, and it was legal discrimination, the majority of the country would assert that the law needs changing, because the majority support freedom of belief and expression much more than labour and tories do.