Have you not lived through the political shit show we've had? Brexit, COVID scandals, Boris Johnson, Farage, stagnating wages, poor productivity, inflation, high energy prices, NHS in crisis, housing shit show.....and there's no end in sight. Think the UK hasn't been doing that badly is quite a willful refusal to see how we compare to the rest of the world and where we could have been if we functioned better.
randomly choosing a random outgroup to collectively hate must be ironically funny sometimes(see: jokes about the fr*nch)
Genuinely there is no other reason. sometimes people will create justifications/other explanations for it but really its just absurdist humor with a pinch of tribalism.
edit: i should add though, usually this type of humor is meant to be ironic by most of its participants. the more i think about it, the more it seems this is more rude than funny.
Economically it's definitely not doing well. Politically it's been a shitshow but many countries have. I definitely hate the situation but not the people/culture/(country) as such.
UK export neoliberalisn,evagelicals and that traitor against all human Boris,UK will not be allowed to live that down for 100 year.
UK stop having shit ideas.