Warmasters - both Gladiator and Barbarians - are fairly proud to begin with. After all, they are the ones who are able to fight without cantrips and relying on theirt own abilities as veterans of the battlefield. They aren't exactly going to just let you run your mouth without doing some talking of their own - and if you didn't already notice ogres, giant and dwarves aren't so much big on words as they are maimings, beatings and beheadings 
If you mouthed off to a Gladitor would you really expect a duel? My gladiators are only to happy to deathmark, kill and perhaps loot you. As a lesson not to disrespect the Warmasters and to teach you to be more self reliable by re-obtaining your armor.
If you mouthed off to a Barbarian, again, expect a deathmark, a slaying and more than likely them to rip your head off as a trophy and display it. They mightn't take your things but would almost certainly jump up and down on them until they were broken (read: in game terms, sacrificed). Don't expect too much but a stomped on bloody corpse and some shards fo metal, pottery and fur when you get back to the scene of the battle.
I think anyone will be hard pressed to make the argument that these reactions aren't good roleplay from a proud, short tempered veteran.
As for challenges - they aren't real battles. No one wants weapons cleaved, hellstreams melting equipment, sacrificing of disarmed weapons, cabal powers used then others don't have them, using of cps to heal all the time, leaving the area and running about and so on. It's a pretty artificial situation that gives some reace/classes huge advantages. I never take challenges too seriously due to this. Another reason challenge-for-rank sucks.
Personally, I've also never had an issue declining challenges from those who simply use the game mechanics to attempt to force a Warmaster to fight on their terms. Fail. I've been known to use ignore to stop people's bullsh!t (as the mortal WM leader no less). Of course, in these situations it wouldn't be fair not to give the person their dreamshot so I would usually arrange a deathmark for you. No need to thank me, its all part of the (not so) friendly L-A WM service reserved for such douche-baggery. 
L-A
derail from original topic>
opinion of cabal>