If Britain was truly not accepting of racism, Nigel Farage would be in jail for promoting that horrid racist poster in the referendum campaign.
If you could show that that poster (I'm guessing which one you mean) was an 'incitement to racial hatred' then I'm sure you could get someone to start a prosecution. Even then Nigel Farage would only be in jail if the prosecution was successful.
If not, then freedom of speech (or of other forms of expression) trumps your feelings of taking offence on behalf of others.