Not read the whole thread.
I think it's because actually, most people didn't know what it really meant at all.
The referendum was rushed as DC said he'd do it, and they all assumed the answer would be remain.
The Brexit people were well funded, organised, not afraid of erm bending the truth. They got some good slogans, avoided specifics, leveraged a lot of comfy emotional stuff and some less pleasant stuff to get people onside.
The remain campaign was a shambles.
There was info on politics progs etc etc. But the papers also mainly ran simplistic messages.
I don't remember a leaflet or loads of public info saying.
This is what we put in and this is what we get out and could (will almost certainly) lose.
I remember someone talking about the Scottish independence one which had a year of run in, neutral factual leaflets to all homes. Loads of info accessible to all levels via various forms (TV etc).
That's why, I think. If you didn't really look into it and you don't really know what the free trade etc meant then as an average Joe yes I'm sure a lot is a shock.
I have less sympathy for eg the farmers and fishing people who were getting grants trade etc etc and really really ought to have known, who are now saying wtf. I mean. Come on.