I'm an European who has been very vocal against Brexit from the beginning. I love the UK, I have family I love in the UK and never understood why a government will commit such damage against their own country interests as to put leaving the EU in a referendum.
Having said that, I think you are way off line to call leavers stupid. People voted what was presented to them in a referendum - leave = all good, millions for NHS, gaining border controls and immigration while keeping the EU single market status quo. This is what people were sold and voted for.
Yes, there were many saying what's being sold is a dud but most people don't take that much interest in politics to research what's the best for self and country.
Don't blame the people, blame the government who lied time and again to get the result they wanted.