|Chinese Gunpowder Green Tea|
There are other teas, though. And those teas require more tenderness than the standard fare. For example, Chinese Gunpowder Green Tea (green tea leaves rolled into small tight balls that unfurl during the infusion process) would almost assuredly go unpalatably bitter were you to pour boiling water over it. In the case of the aforementioned tea, portioning out the amount of leaves you want in your cup, then giving them a quick rinse in room-temperature water before pouring fish eyes over your infusion maximises the delicate flavour of Chinese green tea.
Or, in another case, the age and production of peppermint tea may adversely affect the way the tea reacts to different temperatures of water. The peppermint tea that I'm currently enjoying requires that I pour the water over the bags just before the boiling point, at a heating point known as rope of pearls. If I let it go beyond that point, as my wife describes it, "it tastes more grassy and green than peppermint." And if what you're anticipating is peppermint but you get a grassy flavour, you're probably not going to be satisfied.
All this to say that if you're going involve yourself in the proper preparation of tea, then there are certain teas that simply don't follow the universal rule of "boiling water poured over the bag." However, in all cases, as far as I know, the tea must be present in the cup or pot before the introduction of the water -- and in some cases, the tea tastes better if is given a rinse in tepid water first.
There is a reason why the Asian countries are famous for their teas, and for tea ceremonies: because there is an entire culture and art surrounding the use and preparation of tea. So, while Christopher Hitchens and I agree enitrely on the particulars of his article, that agreement comes with -- I think -- an underlying assumption that the kind of tea we're discussing is a standard black fare, an English breakfast tea, say. There is quite a bit more to the intricate world of tea, however, than boiling water over an already present teabag.