"On a more serious note : I'm not British, but what I see on forums is indeed a lot of heated discussion, generalization, and ad hominem attacks."
And this was "vote remain" did all thoughout their campaign, which is entirely why "Leave" won.
Both sides were fighting different elections. Remain was fighting in the westminster bubble on mass media in this bizzare gladotorial sport between personalities whilst barely discussing the issues except as throwaway comments declaring that their opinion was the one truth and that no discussion or dissenting opinion was allowed.
In my town, the offical remain campaigns major activity was visiting in a sodding huge bus with very few people on it which stayed for a couple of hours for some good pictures and a TV interview, while a bunch of activists stuck up posters with slogans on in places without permission, after which they buggered off, never to be seen or heard from again, leaving the couple of local activists to face pissed off local property owners saying "didn't we tell you not to stick posters on my building"? Guess what sort of effect that had on the morale of the local remain campaigners? I didn't see them campaigning again when out and about.
"Vote leave" meanwhile appeared to be campaigning in the local pub, in the country markets and on the streets door to door discussing the issues. Increasingly hysterical claims that leaving the EU would result in things such as WW3 were pulled apart, each aspect was examined in detail and then discussed to death over a pint.
If "vote remain" had of run a campaign like Jeremy Corbyn with a more civil and nuanced message that he was x% remain and x% leave because $reason then they'd have walked the campaign. Instead the remain campaigns zealots turned a portion of the undecided againt remain while an imported American style adversial message of "YOUR EITHER WITH US OR AGAINST US!!" did a great job of pushing them further towards "vote leave".