Forgive me, but you seem to be swinging from posing as something of an ingénue in your recent posts, not really understanding what the EU fuss is all about, to expressing strong anti-brexit opinions, deploying the extremely tired 'only an advisory referendum'/'we should have stayed in to bring about reform' tropes. You also stated that you think borders are essentially rather silly and unneccessary things, which is fair enough if democracy - the ability to hire and sanction the people who raise and spend your taxes, and make your laws - isn't particularly your thing, but you have to accept that to many of us, it is.
You also display a fundamental misunderstanding, if you'll forgive me again, of what the EU is, for in stating that the 1975 referendum was decisive you entirely miss the point that the EU didn't exist in 1975, and wasn't to do so for another 18 years. Whilst the lie had been formulated my Macmillan and his advisers (who included Heath) as far back as the 1950s, prior to the UK's original bids for membership, it didn't properly coalesce until the Maastricht Treaty of 1992/3 created the European Union, subsuming the citizens of the member states into citizens of the EU, launching the EU Single Currency, and creating the framework for the successor EU constitution (the Lisbon Treaty) of 2007, within which the EU evolved into a legal international entity in its own right. This 2 part process involved a shift of constitutional power from the member states to the institutions of Brussels so fundamental and far-reaching that it cannot but be beyond dispute that the electorates - the reach of whose whose suffrage would be fundamentally diluted - should have been given the right to decide by plebiscite. You and I were not consulted over either Maastricht or Lisbon. Therein lay the foundations of Brexit.