It's as if we have to collect all these cases and read them and deduct what is legal and what is not.
I think that to most people in western culture today, this has become how they determine legal vs illegal. In other words, illegal vs legal, in their minds, is not a function of law, but rather a function of the behavior of political enforcers.
In the words of Confucius though, The beginning of wisdom is calling things by their proper names. My first hand experience has shown me that this is completely true. Words are our minds' handles on reality. Once we clarify the meaning of our words and how we use them, our thinking becomes clearer. When our thinking becomes clearer, we understand our world better. When we understand our world better, our plans to make our world better become more effective.
Thus it is counterproductive (unless you're going into public manipulation/politics, but if you do that you must not be wanting to make the world a better place anyways, lol) to think in terms of legal or illegal; it is more beneficial to think in terms of "What's going to make the world better, at least to me?" and "What's going to get me beat up by political enforcers?" since that's what we really care about, rather than "What does some incomprehensible legal document, which no one, least of all political enforcers, has ever read, say?".
Of course it can be a bit scary to think that clearly. Many of us don't want to admit our world is that messed up. It feels much more comfortable, much more safe, to think in terms of legal and illegal. But, at some level, I think we all know that doing so is living in a fantasy. At some point I gave up on that fantasy, and although the world looks a bit darker than the fantasy, the future started looking brighter because I realized that by choosing to see the world as it is rather than as I wish it were, I gain the power to change it for the better because I plan my actions based on reality rather than fantasy. Of course, I, like everyone, still make mistakes a plenty. I have a long way to go, no doubt, but I remain convinced that this is the right path.