Frankly as an online currency gil is not worth crap. You can get 2mil for 30$ US. Several months ago (pre-wow) it was much much more valuable. IGE no longer accepts gil from players, it only distributes what its farmers bring in. Why? Surplus. The people who tend to buy currency are the people who are already long gone from ffxi, or on their way out. It's kind of funny like that.
I think comparing gil-buying to drugs is a bit harsh. It takes the average person HOW long to farm for 2million? A hell of a lot more time then it takes to earn 30bucks US. There are exceptions but most people will admit that farming is not fun. And to craft you need money to make money.
As for if it is ethical I would say its against the spirit of the game. (I would also say monopolizing any given mob is againt the spirit of the game.) However when making a decent amount of gil is nearly impossible for the average player coupled with the high gear standards... I will not judge. I think the mentality of a gilbuyer is more along the lines of someone spending a couple extra dollars on their hobby than anything else.
As for me I'll keep farming crystals... always good money in that

I don't support the trading of online currency for real money at all, but it seems like calling gil-buyer on someone is like calling them a witch and having the whole village set up a stake and light the bonfire. :wink: