If you want Britain to remain in the EU, don't direct your anger at leave voters in general. Direct your anger at the people in power who lied to them and promised them stuff they frankly never intended of delivering. Many of which, namely Boris and Gove most likely didn't actually want us to leave and were just using this as an opportunity to increase their own power within the Tory party. Leave voters know something is wrong, many of them have been screwed over by austerity, but then were told that it's the EU that is causing these issues. A message reinforced by the media and politicians, who have exploited voters through pure lies. Present that message now it has become increasingly clear.