"so it's right that one side is named and the other is not, right oh!"
Yes, it is, when the alleged crime in question is Rape. Nor is the law unique to the UK. The US have a rape shield law too, as does most of the developed world, for a very specific reason; Rape is humiliating, demeaning, traumatic and potentially stigmatising - if those defendants were named, fewer might find the courage to come forward and put up with the whole court process. Secondarily, by naming the rape suspect rather than the victim, it might encourage other victims of the same person to come forward.
You might have a point, if you could demonstrate that a significant proportion of rape accusations were false, or made-up, or made out of revenge for some imagined slight - but that is not what the evidence suggests. A large British Home Office study looking at this issue concluded that on the best available evidence, the number of false allegations was 3% or less.