The job of sorting it is with the government of the day, plain and simple. If that’s a government that voted remain, I’d hope they endeavor to solve the problem rather than using ‘well they started it’ as a justification for failure.
The job of ensuring general political discourse is respectful, constructive, and conducive to the public good is however shared by everybody. I just do not see any value in continuing to point fingers and say I told you so all these years later, but I stand to be corrected if anybody can come up with a reason.
Long before I could walk and talk I gather there were several moments of general unity amongst the British people. It seems it was often during such times that a lot of shit got done and the national mood improved. All of the most effective political revolutions came from mobilisation, rather than division, of the people. And my word the UK needs political change ASAP.