Whether we like it or not, we are all manipulated on a daily basis. Sometimes we are aware as it happens, other times with hindsight but often we are blissfully unaware. This is not related to our intelligence but more often the skill of the people manipulating us and our own predictable human traits.
Those adverts on the television we think are rubbish, aren't rubbish, they're just not aimed at us. The ones we think are clever, funny or relatable, probably are aimed at us and I am certain that we've all been persuaded to buy something because of an advert whether we realise or not.
Politics is no different and there are those of us who will be influenced one way or another by what is essentially clever, or even underhand, marketing from all areas of the political spectrum and in this case both the leave and remain campaigns. For people who had an opinion on what they thought was right beforehand (whichever way that opinion fell) and remain unchanged in that opinion, this 'marketing' will likely have served not to change their minds or opinions but to re-enforce their belief that they are right.