This says, you can not kick player with no reason and the reason can not be denying loot(kicking before loot to avoid giving fair chances).- Kicking players from raid for no reason, especially before distributing loot from boss kill that they participated in.
In this case, there was a reason to kick this player. You don't need to add any rules before raid starts about this, players can not disagree with this, it is unalienable power of the raid leader. Any specific reason for kicking are not stated in rules, so it can be anything with the exception of "kick with intent to not give loot". So "making a mistake" should be completely valid reason.
Or any reason has implication that loot will not be rolled and can be considered as "intent to not give loot", as it seems to be the case here. But then rules would clearly state "you have to distribute loot for eligible players, before you remove them from raid with your valid reason".
Edit: Since this rule is in ninja policy, it has nothing to do with kicking players with no reason, which means, you can kick players with no reason as long as loot is split fairly. And to kick player with reason you don't have to give loot as long as reason is not to ninja that loot.
All this leads to conclusion that leader does not have to gain any powers over looting, and can kick players without giving loot, and in this case player provided sufficient evidence that he was kicked with intent to not give loot and sets precedent that making mistakes, wasting time and wiping raid is not a sufficient reason. Despite these rules existing, there is no such variable or premise as players level of knowledge or behavior threshold available to be set by raid leader. Sufficient reason to kick players does not exist, despite the rules saying that there is/could be, implied to be open for interpretation by players and to agree upon them. You have to split the loot before you kick them. This rule is pretty much "got you tee hee" rule and should be moved to "social mistreatment" or whatever(getting people save and kicking them, since it would be absurd to put in ninja rules some "potential items that player could have gotten"). And instead rule should properly relay that you must split the loot before removing player.
Players have powers to set their looting rules, this rule is based on that. It was stated before the raid started that all items are in leaders discretion to give or not to give without any conditions. Loot rules were not changed, not giving any item to any player for any reason was within looting rules. There is not specific exception with keyword "reserved" as you can demonstrate the same intent with "loot x is mine", "loot is at my discretion". Intent of the rule here is "leaders can not break rules they set an players agreed upon".- Changing looting rules during the raid, after it has started.Example: You joined a raid that was being advertised as one with no reserved items and after first boss raid leader says that he reserves item x from last boss.
I hope my interpretation of these rules are reasonable, though it might as well not be, since I don't have a degree in looting laws.
Soo,
You can kick players for a reason, as long as reason is not to deny loot. [no you can not, this precedent]
Your rules can not allow players to have 2 or more chances on the same item.
You can not take/give items without rolling, unless it's agreed otherwise by everyone.
You can not change looting rules after the raid has started.
Any rules you make within these limits are up for players to agree upon.
In this case, leader had powers over all items, as they agreed and is perfectly allowed. As outcome of rules allow such concept as "reserved", despite it not being specifically stated as an exception, but rather an outcome of player agreement. Yet GM intervened in agreement between players, despite everything being within set rules and limits of freedom allowed by these rules.