The Death of the Author debate is way too blinkered in scope

[Lethologica]

The problem is that it often should be the last word. "Gandalf was totally toking it up for the whole Lord of The Rings series, because "pipeweed" is obviously marijuana" is not, and should not ever be treated as, an argument equally valid as "Pipeweed is obviously tobacco, but calling it by that name is incorrect, because that word derived from Spanish tabaco (from American Indian origin), would have seemed linguistically out of place in Middle-earth."

LotR is a work where authorial context looms particularly large, yet one could refer to the text for that:

There is another astonishing thing about Hobbits of old that must be mentioned, an astonishing habit: they imbibed or inhaled, through pipes of clay or wood, the smoke of the burning leaves of a herb, which they called pipe-weed or leaf, a variety probably of Nicotiana. A great deal of mystery surrounds the origin of this peculiar custom, or 'art' as the Hobbits preferred to call it. All that could be discovered about it in antiquity was put together by Meriadoc Brandybuck (later Master of Buckland), and since he and the tobacco of the Southfarthing play a part in the history that follows, his remarks in the introduction to his Herblore of the Shire may be quoted.

He produced a small leather bag full of tobacco. 'We have heaps of it,' he said; 'and you can all pack as much as you wish, when we go. We did some salvage-work this morning, Pippin and I. There are lots of things floating about. It was Pippin who found two small barrels, washed up out of some cellar or store-house, I suppose. When we opened them, we found they were filled with this: as fine a pipe-weed as you could wish for, and quite unspoilt.'

I suspect it's read as weed by some people these days largely because of the movies, which are a distinct work with a decidedly different authorial context, and make a number of stoner jokes. And also because an increasing number of people today have marijuana play a similar role in their lives as tobacco did in Tolkien's. And because LotR became associated with '60s counterculture due to its environmentalist and anti-industrial themes. All of which is a lot more interesting than "it's baccy, end of story."

To pick another well-worn example: what color is the sky in the opening scene of Neuromancer? Different generations have parsed it as glowing gray, as black-and-white static, as harsh BSOD blue. Gibson can only have intended one of them, likely the first, and yet each of them leverages a distinct power over its audience, because of course the real meaning here is the pervasive and oppressive technological ethos of a dead-channel sky, which is the meaning directly expressed in the text.