And I totally agree with you on that, but that's not what "judge by thinking how good you'll look 50 years from now" is. Filling in the details is more "applying the spirit of the law to a particular case not explicitly covered", it's not about creating new de facto laws based on your personal (political) opinions.
Where do you think the "spirit of the law" comes from and how does a judge apply it? It's by thinking about what others would expect. Whether it's about the past (original intent) or the future, this is an act of imagination (supported by research) where they are thinking about what others would want. There isn't any "view from nowhere".
If you don't care about what other people want and how the law affects people, then there is no morality or justice and it might as well be a coin flip.
