While it may be one thing for an investment banker to understand that they ‘benefit from the EU’ in regulatory terms, it is quite another to encourage poor and culturally marginalised people to feel grateful towards the elites that sustain them through handouts, month by month. Resentment develops not in spite of this generosity, but arguably because of it.
This is the best piece I've read about the root causes of the Brexit movement, and it carries with it extremely important lessons for the United States over the next several months and years. See also this thought-provoking piece on the importance of dignity when it comes to how people vote. If you don't understand the Trump vote, this should clear things up rather quickly. It did for me.