Nobody's arguing that friendly fire can't be avoided - just that it can't be avoided 100% of the time. You can be as situationally aware as anything, but that won't necessarily acount for freak moments that sometimes just happen.
And nobody's situational awareness is 100% perfect, not even yours, so there are plenty of situations that could, technically be avoided but simply won't 100% of the time. I don't think pilots should be penalised for not having 100% perfect situational awareness (especially when so much of that can depend on having kit which allows you to view your surroundings), but there's a long way between having slightly imperfect situational awareness and being reckless.
And the recklessness goes both ways. Why is it the trigger guy's fault, why not the person who recklessly flew into your line of fire? Why don't they share any of the responsibility, eh? Seems to me that flying into someone's active firing line is even less situationally aware than having your firing line flown into.
I would describe my firing habits as overcautious in most scenarios, and I still have got caught out once or twice. Friendly fire WILL happen, is the point, and the question is about whether the current rules adequately recognise it, and it seems pretty clear that they don't.