Maybe look at some of the messaging in the Brexit campaign?
Turkey to join EU, flood gates open to 85m Muslims, illustrated on a map showing Syria and Iraq... look whats coming next!
Then there was Farage's We are full poster, all the people in the column of refugee's were dark skinned, the origins of the poster was Nazi Germany....
Its extremely naïve to imply, as you seem to be doing that racism had a marginal effect...
Take the racist vote out of the referendum and Remain would have won by a huge margin.
This was in a letter Bojo signed to Cameron pre vote... "the public will draw the reasonable conclusion that the only way to avoid having common borders with Turkey is to vote Leave and take back control on 23 June"
..and he wasn't the only one to lie about this... but Bojo knew very well Turkey would never join the EU, it would be vetoed but they stoked the racist vote, because if Turkey was a rich white and Christian country, there simply would not have been the fear...
Subsequently Bojo lied and denied ever talking about Turkey.