I think you miss the point I am making when I mention coffee, Strollin' Johnny. Obviously coffee has different effects from pot, just as is the case with alcohol and nicotine and theobromine (the active constituent in chocolate). What they all have in common is that are are all to some extent habit-forming, and they all have some psychoactive effect. By that I mean that people use them as a way of adjusting their mood and so forth. And it is definitely possible to take too much caffeine. (And in some cases it can have very serious effects)

And if any of these substances were made illegal, it is absolutely certain that there would be dealers selling them, and that in many cases these dealers would be ready to supply a range of other drugs. And I think it is pretty certain that there would be some people who would experiment with the other drugs on sale. What makes something a "gateway drug" isn't the fact that it is a drug, but that it is illegal.

Chewing gum would do as well. I believe in Singapore, where chewing gum has been illegal for the last 12 years, there is a flourishing black market - and I note that the Singapore government has recently relaxed the ban, though only for registered users, for medical purposes, from pharmacies Singapore lifts ban.

...............
When a comparison is drawn between two things that does not imply any suggestion that they are alike in all respects, but merely that in a particular respect or respects they have something in common. Which is rather obviously the case with horses and dromedaries since both are mammalian quadrupeds used for riding. But that doesn't mean that someone pointing out this commonality is under the impression that horses have humps and so forth.

I have noticed that people often seem to respond in this way when people make a comparison or draw an analogy, for example between two historical situations.