> instead of insulting the people they were supposed to convince (as the Remain campaign did)

Can you point to any examples of this? I don't think the official Remain campaign did anything of the sort. Insulting the people you are trying to convert is a poor strategy, which is why I don't believe they did it.

When you say "were called bigots, uneducated, stupid, racist, etc", what I think happened was that the Leave campaign alleged that that was what the Remainers thinking/saying and it gained traction.