My point is that any principle is going to hit edge cases when applied in real life, and so "instead of acknowledging that there are in fact absolute rights - we constantly debate where _the line_ is" is actually the right thing to do, because principles are not absolute rights, and edge cases in fact need to be solved.
It sounds as though what you want is the The Constitution / Bill of Right. A basic set of simply worded principles that influence the definition of law, but aren't themselves "the law".
There are absolute rights, and debating where the line falls is pointless. But when applying it to the real world, you need flexibility (i.e. debate where the line falls).
Anyway, isn't that basically what we already have, with free speech? It's legally protected in even extreme cases where it arguably causes more damage than value, but per event it tends to go through courts (or there is enough court precedence to make that wasted effort).
Court precedence applying flexibility to an absolute intent/right is the debating of the line. Isn't it?
Most edge cases, in fact, can just be managed—they don't need to be solved.
With people, I would argue that not solving edge cases and just managing them when they arise should be the norm. People are messy, and our system should have enough slack in it to act humanely in the vast majority of cases. We really don't need hard and fast rules to cover everything, just "normal" things.