I guess so. Fire may not be considered an attack, as it can be a natural hazard - e.g. natural lava flows which create natural forest fires, etc.
Likewise, Skeletons fire arrows as a natural hazard, so maybe the game can't differenciate between what is natural or unnatural.
Personally, I don't live PvP. If it gives some people their kicks - good for them. People will always try and exploit the system, though.
If you are carrying Diamonds around with you, it's foolish not to wear armour, or not to have weapons. Not talking about players here, mobs too. But being a douche can't be excused.
I've seen quite a few threads around - ban requests - for people 'Flint 'n Steel'ing' people. I don't care who is in the wrong, but I've seen too many cases where the innocent party has retailiated. For example, Callum (Italay). Whether he is innocent or not, or if Quanix is innocent or not, they have both attacked each other and tryed to get revenge. If you are truly a victim, please, don't retaliate. Ask for a ban, or for an admin. Like you ask for a revert on Classic, rather than fixing your own build.
It would just be better if everyone just got on better.