But you ARE defending yourself from attack, regardless what 1 or zero is set in memory at the time. This is exactly the issue.
You may see it that way, but what matters is what the rules of the game state. And since a game needs to have clear-cut rules, we have a very simple system which works well for everyone (and fits quite well with the dystopian, arbitrary, shoot-first mentality that permeates the universe of ED): if you don't want the law to side with you, turn crimes off. If the opposition turns crimes on and are clean, well, you did shoot first as far as the crime system is concerned and that is all that matters. It is entirely fair since you had the option of using it to your advantage in the first place but opted out from your own volition.
Now of course that can interfere with casual, for-shoots-and-giggles PVP if somebody is acting in bad faith and has their crimes ON, but again that is entirely fair. You know how I always repeat to the Mobius whingers when somebody invades their group, that private groups give the owner 100% control over who gets in and therefore that it's their responsibility alone if someone manages to worm their way into the group to break their gentleman's agreement? The exact same happens here. If someone is abusing your trust, simply don't engage in PVP with them, or at least not on your usual gentleman's terms while your pants are down and your crimes are OFF. Or do it in an anarchy system, where all of that is irrelevant.
But the heart of the matter really is that PVP is a means to an end, not the end itself. If you engage in PVP for the sake of PVP and open yourself up to abuse by turning off crime reporting, don't be surprised when somebody who does see PVP as just a means to an end (so, to kill you, rather than just enjoy a good fight) uses every tool at their disposal to achieve their goal.