Don't project your own fears of inferiority onto other peoples arguments.
Anybody who claims to understand enough about the EU to make a competent fully evidence-based decision is almost certainly lying. The only thing we all understand now is that the process of disentanglement isn't as simple as we were told (although I think that was pretty obvious from the start).
A simple argument for a threshold (maybe not as extreme as 66%) is that it's a decision that incurs years (possibly decades) of work and an immense cost attached.
You don't move house because you saw a picture and you think you might like the new one.