Mrs. OW, I've been there myself. I purposely allowed myself to be wowed by the most extreme fringes of Brexit thinking and populist appeal politics. I geed myself on to more and more heated viewpoints and Year Zero cultural thinking. True believer status felt so right and so comforting that I eschewed all data and other PoV. I never stopped arguing in good faith with people, or attacked my "opponents", but a comfort blanket wrapped around me, and I was a hugely annoying and pompously opinionated prig (no typo? lol). It felt good to have an outlier fixed opinion, and even better to demean the other side. FFS, I even warmed to Trump during this period, so fired up was my temperament at the time.
That's really not who I am, who I was. And the reading of data driven blogs (Chris Grey in particular) on Brexit challenged my opinions, and I gradually over 12 months came up for air.
I haven't had any epiphany to think totally differently on Brexit, I've just broken the Möbius Loop of thinking and negative emotions I had during that period, and now welcome being challenged from both sides of the argument.
My point is that self radicalisation, willing participation in herd mentality, and visceral enjoyment of purity spirals is so easy to slip into, but can be very hard to extract from.
And I do believe that the more polarising/zero sum game/pure matter of identity marker and subjective belief etc the "crusade", the more the doubling and trebling down is required, the more the attraction of group dynamics is magnified, and the more brutal the purity spirals are amplified. And this is TRA and it's hold amongst the broad range of elites/older liberals/younger activists.
And if your "group" is the group running society, how are you gonna deviate from the group even if doubts are entering your mind?
Are you really gonna want Patrick Stewart to think you're a transphobe, or liberal politicians to think you're a bigot, or doctors to think you're ok with trans youth at risk of suicide, or journalists to think you're prejudiced, or teachers to think you don't have the best interest of youth at heart, or feminists like Caroline Lucas to think you're small and inhuman in putting down individuals who only want acceptance and that your narrow mind puts this ahead of environmental armageddon, or teens/family/friends/work colleagues who won't ever allow the homophobia of the 70s and 80s be carried on by you in the new transphobia.
How do you break out of those herds and spirals? De-programming from belief in hard Brexit is a doddle in comparison.