melee combat (you know, the entire point of the game).
Wrong.
If you don't like dueling someone that has a shield, STFU and bring an axe next time, or just swing around the shield/kick like the good duelists do. And chill with the elitism about what you consider "real" dueling.
True!
My first quote was meant to introduce my opinion that all playable classes are equally authorized in all gamemodes, so I support you on shield usage in duel server. As in all other things.
In battle/siege servers everyone's forced to fight every kind of builds of the opposing team, so there is more room for rage, but in duel server you CHOOSE your duels. If you dont like someone's playstyle its extremely childish to bother him, when you are not even forced to suffer from him.
Then there is some douchebags that trollspam you with request even when its clear you dont want to duel them, but if someone uses a shield and dont brag behind it (the typical coward shielder), I dont see the point in people complaining. Except for good old verbal duels, which is also a part of the duel server life.