While I respect your guy's views on why none of them has been a really strong answer. Typos and clan tags, yeah I get it. But "getting away with something"? I don't understand if you have someone change their name they are still subject to the general server rules regardless of name change. Offensive language or improper behavior is treated the same way regardless of who's name it is. RP eh that's subjective do you realize in those times how many people assumed disguises to enter anonymously into tournaments so that people wouldn't shy away? Or how easy it was to escape trouble by just running to a new town and changing your name?
They are not talking about getting away with having a name.
They are talking about when a player joins a game with one name. Breaks a rule and DC's, comes back with another name. It makes it hard for admins as well as players to keep track of the person so they can get punished.
They also do not want people changing their identity willy-nilly for this reason, as well as people abusing this in strat.
Imagine a clan of people changing their names so they can join a strat battle they would otherwise not be invited too, then leaving to sabotage the whole thing.
(This is punishable and everything but it just creates more unnecessary work for admins.)