Was it really that open minded though really.
I remember the promoters of Sunday Roast in an interview, saying one of the reasons they started Roast was that black people were constantly getting turned away from raves, so they decided to make their own thing.
There were black people at raves bitd but as happened at alot of places there was a probably a quota system in place which would have undoubtedly been at the behest of the promoter. Behind the PLUR ethos of the scene, the racist attitudes of British society still existed. Yet for the time, i still think the scene had a relatively open minded attitude. However i do remember there were alot of complaints in 93 going into 94 by ravers saying that the vibe had become moody. A lot of this was just a euphemism for black people. I think as the colour balance at raves became more mixed, it made alot of the white ravers, esp those from the suburbs and provincial towns feel a bit uncomfortable.
While i think that most working class white men now accept Black people in the UK as being British, that doesn't extend to Muslim people, which over the last couple of decades, has brought racism/intolerance back to the fore.