Yeah… unfortunately, confusion about this particular subject exists because members often look for the underlying justification on things and then extrapolate from there.
(I’m going to paraphrase and shorten things a lot here so we don’t have to dive into definitions and technicalities. Bear with me.)
The doctrine brought forth about this is what’s referred to as “The Word of Wisdom,” which was a short outline of what things were deemed as “harmful” or otherwise “unsuitable” for the body. The idea being that the Lord was promising to people that if they didn’t ingest these things, they would live a healthier life as a result. “Hot drinks” was mentioned and clarified a century later to mean “tea and coffee.” Furthermore, “tea” refers to black and green tea, and not necessarily herbal tea.
People, by nature, want to understand the “why” behind things. You also have people who want to understand where the line begins and ends so they can tiptoe it. Enter the rumor that since the “hot drinks” referred to “tea and coffee,” they both have not-so-insignificant amounts of caffeine in them. Obviously that must mean drinks like Coca-Cola and Pepsi, plus foods such as chocolate, must also be in violation of this, right?
Well, the issue with that is people think they’re applying “the spirit of the law” (meaning the larger picture behind it) when they’re actually applying “the word of the law” (taken at face value). The idea behind the Word of Wisdom is to take care of your body by having a balanced diet and not eating too much of a particular thing. Certain items were called out explicitly; if caffeine were the true issue, then it would’ve been called out instead. But it wasn’t, and there have been some clarifications to emphasize that caffeine itself is not the explicit reason behind it. (However the idea of “addiction” could extend to caffeine if someone were to consume large amounts of it regularly, but addiction or dependency can occur even to things like Tylenol when too much is consumed, so targeting it specifically is silly.)
So in short, it’s a mixture of misunderstanding and overzealous practice. Caffeine is perfectly fine. Just like anything else: make sure you’re not consuming too much of it.
I had to think about this. I can’t seem to find any articles in a quick search where church leaders (a Prophet or Apostle) explicitly forbade its use. I have, however, found many excerpts where leaders who do not sit at the head (Quorum of the Seventy, BIshop, etc) have made statements warning against it or even flat out saying that members should not ingest it.
Given the structure and lack of corrective statements coming from above, I would attribute the confusion to local and regional leaders being overzealous by including caffeine explicitly in their teachings. Some have worded things in a manner I would find accurate, such as “high-dose caffeinated energy drinks” or “excessive soda consumption which results in high caffeine and sugar intake.” Others though explicitly call out caffeine as an “evil,” describing experiences with caffeine withdrawals or members deciding to not ingest alcohol, nicotine, nor caffeine. These mentions seem to have drummed up confusion primarily in the 80s (a lot of “Letter to the Editor” publications from this period seem to have been back-and-forth arguments among members, lol).
Initially I didn’t think the history is as “long” as you claimed, but then I realized that the 80s was just forty years ago, and with some results of the topic dating as far back as the 70s, it would mean it’s been an intra-member debate for almost half a century. And half a century is practically a lifetime 😖