This is not actually that much of a sensation -- the judges have made it clear at the very beginning that it is not their place to define what is sex or gender. The only thing they do is clarify how the words "woman" and "man" are to be interpreted in existing laws that have been made to protect women (e.g., and usually, from men).

And the result is: it is the judgement that those laws are referring to the biological sex (which it itself is recognised as being subject to some debate, too, so the judgement refers to another common definition).

That's all. It is not a redefinition or anything. I cannot really understand the enthusiasm of one side or another. It just clarifies what those laws were meant to say, and I tend to agree that anything else would most likely be an unintended reinterpretation. The judges also make it clear that if law makers want more protection for other groups, e.g., trans people, they probably need to make more laws for that.

I also find that this is a very complex topic, because it was about the question whether in sex separated prisons, it is more important to protect trans women from cis men, or to protect cis women from imposter trans women cis men. I mean -- who knows a trivial solution to that? The judges clarified basically that the original law was probably just concerned about protecting cis women from cis men, because probably no-body thought about it. And for the sake of clarifying anything, they said that "woman" probably meant "biological woman". They were tasked to decide something, so they did.

And, well, at least that's I read into this... You can have a look for yourself, maybe, before taking one side.