If this was a specified RP server, RP names would be one thing. But it's not.
While EQ is an MMORPG, we all know that almost no one roleplayed on a non-roleplay server.
So, I say get over it, either /ignore the person if it bothers you that much, refuse to group with them, or whatever else you feel you need to do to enjoy your game.
Here is an idea. Form a Roleplaying guild and have a strict admittance policy on naming
[You must be logged in to view images. Log in or Register.] Play with these people almost exclusively. Mock the people with non-RP names in guildchat, or group chat, as you and yours have fun in EQ your way.