That is far from unusual. And you are right about Brexit hysteria.Strangely enough, this year I've found that more people seem to be revealing that they did vote Brexit. Other people have been told that many members of their families voted Brexit that they were unaware of.
Myself, I've three school friends I've kept in touch with and I've known them for over fifty years - until this year we had never ever discussed politics and I made some casual remark about how stupid Brexit is and found out by chance that two of them admitted to voting Brexit. These are not stupid people and I get the impression that they were not into politics but just dragged along by the brexit hysteria and now don't really know why they voted for Brexit, there was a vague reference to refugees - I said you can't be serious.
Disliking the EU for no apparent reason was very normal. It became the thing to do so to speak.
Just like voting for Boris. Although I would say that of the people I knew who admitted to voting Tory, more did it because of Corbyn. Herd mentality has a lot to answer for. Because so few people want to think for themselves, preferring to go with the flow and hope it will be ok.