Happily!
Chapter 13: Explosive Items
Titans may be used IN ILLEGAL AREAS (red zones)
Chapter 11: Red Zones / Illegal Areas
Red Zones are KOS
You are not inside of the illegal area, you are outside of the area. Your titan rocket was eventually inside of the illegal area, but the titan never was.
This is just not how these words work. You are not inside the illegal area, you are using the titan outside of the illegal area. He is dying in the illegal area, under your logic, can he kill you because he is inside the illegal area? Even if you aren't? Or can he not, and only you can shoot in but he can't shoot out. None of this makes sense.
Chapter 10: New Life Rule
If you die for any reason apart from dying by an Arma bug you may not return to that area for 15 minutes. (1 Kilometer from where you died)
When you shoot into the NLR zone from outside of it, you are returning to the zone. When you understand, or pay attention to, the purpose behind these rules it becomes more clear. NLR is supposed to prevent people from returning to an area quickly and fighting after they die. This is for RP purposes, once you are dead there is a punishment and you can't return. If you can just shoot into the zone with a Titan, or a mar 10, or whatever, that would defeat the purpose of the rule. This is common sense, not every scenario is written down in the rules, particularly when they are very easy to infer from the text itself.
I agree that there is nothing in the rules explicitly saying not to do something like this, but it's sort of common sense. Disputes are meant for conversations about the server rules, not the game. I'm not sure why you offered him an epi with a dispute, if it was because you broke a rule and he died because of it I would think that's fine. But if you are using the dispute system for any in game conversation you couldn't otherwise have it's probably "dispute abuse". That said, I agree it's weird there aren't any rules about this anywhere (though it does sort of feel like Fail RP)
I saw your dispute, you showed a misunderstanding of the server rules and practically admitted to what we all saw in your video.
Sadly, you broke the rules in front of an admin. Admin's don't need documented evidence to ban players they have seen break the rules. Especially when their suspicions are confirmed by a confession. Next time, don't say exactly what you did unless you are certain you didn't break the rules.