People like you amuse me so much because you take something totally random and blow it up into this huge deal over nothing when all you end up doing is making yourself look idiotic.
First off, who the hell are you, out of nowhere to question anyone about anything? Last I checked there's no Fashion Police in FFXI busting people for minding their own business. This wasn't a person who showed up to merit in level 24 gear. This wasn't someone who answered your shout for a mission or quest. So your opinion of what they are or are not wearing in their own personal offtime means precicesly dick. You don't know what they were doing in that gear, and since you had nothing at all to do with this person other than a random check, it's none of your goddamned business anyway.
Let me school you some since you seem to be having some difficulty. There are BCNMs you can do solo or duo, naked, and on a moment's notice. If a friend asks me to help out on a BCNM 60 on a whim, which I generally don't do, I'm not going to go out spend a million gil and pimp myself out on cap gear for a 15 minute cake-ass BCNM that may or may not drop something worth a quarter of that. I'll have some sweet pieces saved from CoP cap gear maybe and fill in the rest with stuff that will suffice. It's what you call common sense. You should try it sometime. Like by refraining from posting this kind of stupidity.
If someone shows up to fight an hnm in this, then you have a right to question that logic. If they come to dynamis or limbus or even sky in this, yeah, I can see saying something. But to go seeking some random person out just to try to make them look bad and degrade them is pretty pathetic, and you need to find something better to do with your time.