If you had a well-documented position on why that's not (one of) the answer(s), we would be happy to hear it. If this is all what Leavers have to say, on the other hand, yours will be a self-fulfilling prophecy.
Of course that is not satisfactory. "The market went down because of X". For whatever reason people need to read that even knowing that X is nonsense.
Not to mention, it was only like 3 weeks ago that every outlet was predicting a global recession. This prediction is almost certainly wrong as well.