I've usually seen folks just handwave x amount of time to change into a different set of gear, usually accompanied by "walking offstage" basically to show their departure to do so. The quickchanging mechanic is literally just an MMO mechanic for quality of life - saving gear sets so you can switch quickly to them depending on what's needed. I don't think it's ever actually mentioned in the lore; you just "gain" gear sets as you unlock additional classes.
That said, I have seen some people work around it so they "can" quickchange. A magical item that "stores" a single suit of armor or something of the like, or some variation of glamour that somehow creates tangible gear. However, those seem to be more the odd ones out rather than the norm. Whether or not such things are okay, though, is up to the RP group. You've already stated that for your RP circle it isn't allowed, so that's basically the end of it - especially if he's being rude and disrespectful about it. I'd say see his explanation if they were cordial and polite about it, but being mean just makes me less inclined to work with someone.
And really, just another point in my own mind I want to bring up... what does it really add? Emoting walking off or otherwise spending the time to change outfits isn't horribly difficult. The only time quickchanging would be useful ICly is if you're caught with your guard down - you're in a bar and SUDDENLY BANDITS or something. Unless that's a horribly regular event to the point that people would feasibly require being able to quickly change into their battle gear, I don't see it being necessary.
And even then, there's technically work-arounds. Chachan was part of a major plot where there were rogues after him and his friends for an item he had in his possession. So he just started wearing more armor in general when walking around - and I've even frequently made mention that he's lined his smithing clothes with a thin layer of chainmail just to be safe.
That said, I have seen some people work around it so they "can" quickchange. A magical item that "stores" a single suit of armor or something of the like, or some variation of glamour that somehow creates tangible gear. However, those seem to be more the odd ones out rather than the norm. Whether or not such things are okay, though, is up to the RP group. You've already stated that for your RP circle it isn't allowed, so that's basically the end of it - especially if he's being rude and disrespectful about it. I'd say see his explanation if they were cordial and polite about it, but being mean just makes me less inclined to work with someone.
And really, just another point in my own mind I want to bring up... what does it really add? Emoting walking off or otherwise spending the time to change outfits isn't horribly difficult. The only time quickchanging would be useful ICly is if you're caught with your guard down - you're in a bar and SUDDENLY BANDITS or something. Unless that's a horribly regular event to the point that people would feasibly require being able to quickly change into their battle gear, I don't see it being necessary.
And even then, there's technically work-arounds. Chachan was part of a major plot where there were rogues after him and his friends for an item he had in his possession. So he just started wearing more armor in general when walking around - and I've even frequently made mention that he's lined his smithing clothes with a thin layer of chainmail just to be safe.