I feel so exhausted constantly arguing on gil sellers. I don't like the gil sellers. I can't respect players who buy their gil that support their behaviour. I can't respect people who beg for money (or even just ask pure strangers). I don't like botting.
However, after reading soo soo soo soo many posts, I'm taking the complacent approach and there is no other way to deal with these guys because honestly, you're going to have to take time out of your day to do this.
1) You could camp with them and try to steal hate from them and run their NM out of the area.
2) You could go and harass them (but then a GM could be on you for that.)
3) Just let it go. Unfortunately, just like there are immoral people in the real world, immoral people in the virtual world shouldn't be too much of a surprise. They're probably voke spamming but like someone else said, I've just started to treat them like other players. If I can't get Hoo Juu the Torrent (I've lost out to him seven times now), then I just accept that I'll eventually have to try harder. Or farm for the item.
I wouldn't bother harassing them or sending them tells. Why would they talk to you? Sometimes people you ask looking for groups don't answer your tells so this could be the same attitude.
BTW, when you talk to a person who is camping a NM, even just REGULAR "LEGIT", the time they take to respond could be the time the NM pops so in the split second, they're replying to you, they could have lost out on the NM. I think it'd even be a strategy if you're trying to get the same NM. (Send a message to all the people camping, and hope it spawns while they respond....)