Where did I say that? Read what I wrote again before you comment on my ignorance. The Leave vote gave rise to an increase in racist activity, from Tommy Robinson hitching his wagon to UKIP to posters like in the one in question, of that there can be no doubt.
And I’ll think you’ll find that there will be no decrease in immigration henceforward, but a definite increase in people coming in from the Middle and Far East and the Indian subcontinent. That will please whatever fraction of Leave voters who were racially motivated no end, I’m sure.