“You mentioned that tea might only be in drink form, that we need to avoid the tea plant. If one takes green tea in pill form they are not only getting the exact same thing into the body but also the caffeine, which is ‘addictive’.” (Lindsay)
As I said before, the Lord has not revealed that any one substance in teas is the reason for the prohibition.
One interpretation of “hot drinks” is that “drinks” is literal and refers only to those substances when one drinks them. That may be an incorrect interpretation, but it is one possible interpretation.