In this argument I can see why both sides think the way they do, and I can understand why. Let me elaborate a little.
I think the idea of putting the chest outside the dome was one of the silliest ideas they could come up with and should definitely be removed by the developers if they do not want things like this to continue. It was obviously put here to troll players in game just to get a good laugh and I am sure they were not trying to get anyone in trouble. However, I can see why you were kicked from the server. If a new person was to come on to MCSG and read the rule page, they would see that there is no direct rule against block glitching to get to a chest. However, looking at your stats, I can see that you are no 'newb' and therefore know that block glitching to get to a chest is not allowed. Therefore, you should not have gone for the chest in the first place.
I can see where you are coming from and I do believe that the chest should be removed to prevent further incidents such as this one from happening. But please, if you know about a rule, do not break it, even if it is not in the rule book.