If the vote was about not taking any kind of economic risk whatsoever, then yes, Brexiter's have been stupid. However, the issues went far beyond economics. You mention the "Iron boot heel of EU tyranny", and while you may feel that comically exaggerating people's concerns may make then look stupid, sovereignty has long been an issue. It was the issue of sovereignty that largely factored into Labour's policy of leaving the EEC (Precursor to the EU) in the early 80s. They were concerned that the EU might impose corporatist policies on the UK amongst other things. Jacques Delors managed to convince them that the EU would only impose socialist policies on the UK and they were soundly fooled by this and dropped their EEC objections. Some prominent Labour MP's like Tony Benn never believed him and never dropped their objections.
I personally have objections to the EU over it's neo-liberal policies (they approved CETA for one!), it's destructive austerity-pushing and anti-democratic activities. Many people in the UK feel we should never have had a referendum, although that is mainly because they lost. Referendums are an important part of any democracy and are in fact an act of true democracy, rather than the representative democracy we are usually lumbered with. The EU has a history of bullying countries into refraining from holding referendums, ignoring the results (e.g. the EU constitution becomes the Lisbon Treaty) and even harassing countries into holding them again when the "wrong" result occurs (Ireland and the Lisbon Treaty).
The other issue with the EU is that it is not content to simply remain a loose coalition of countries engaging in economic cooperation. There is an inexorable march towards something much more like a superstate, and the UK is far from the only member to have concerns about it. This process has only accelerated under Commission President Jean-Claude Juncker. For example, there are moves toward having an EU army and countries like Sweden have strong objections to this. In 1975 the people of the UK voted to approve membership of the ECC, a fairly loose nine member organisation. They did not vote for a 28 member EU with far tighter integration. Whether you like the EU or not, this clearly demonstrates that it is an organisation than can change quite dramatically over time, and it's not always for the better. Many people are unhappy with that level of change and the associated unpredictability. Furthermore, you cannot rely on national democratic forces to bring a halt to superstate ambitions. The EU has demonstrated time and time again that it is willing to ignore, subvert and do end runs around national objections to its future plans. We've seen this most clearly over the EU Constitution and Lisbon treaties.
Before the referendum, I talked at length with other socialist friends about the EU, and they agreed there were serious issues over democracy, neo-liberalism, austerity etc . Yet as soon as the result came out, they became completely polarized. Suddenly the EU never did anything wrong, everyone was racist (because of course, that is the only possible reason anyone would want to leave the EU) and they even seemed to want Britain to fail as a result, presumably to teach Brexiters some kind of lesson. Both sides have acted reprehensibly since the referendum with childish attempts at marginalizing each other, name calling etc. We've had older people calling the younger generation "snowflakes" and the younger generation even calling for the disenfranchisement of the elderly because they are old and won't have to live with their decision (presumably this would also have to apply to young people who are terminally ill or have chronic life-threatening conditions).
People need to take a step back, calm down and accept that there were both good and bad sides to the EU and move on. There will certainly be economic challenges ahead, but outside of the EU we will be able to make international deals more quickly, so there certainly is a chance of success. Regardless of the way people voted, they should be hoping that we make a success of it.