By the way do British people hate immigrants that much? As far as I understood you don't even have that many migrants coming lol (according to this at least: http://www.bbc.com/news/world-europe-34131911), please correct me if I'm mistaken, I'm just trying to understand your point of view.
The UK tabloid press has ran a decades-long campaign of demonising the EU and immigrants to the point where some parts of the population (not saying this is everyone who voted Leave, before anyone jumps on me) sees them as sub-human, or at least sub-Englishman. As much as I believe free-press is important, It sickens me to my core that it's been allowed to get to this point.
After years of being told that immigrants are going to eat your children, or stop you have electric kettles (these are about on the same level for a Brit), well, some people believe anything they read.