I was reading this the other day, and was surprised, since I had never really entertained the idea that a coffee bar might not offer soy. It's become so ubiquitous, not just in cafes, but American culture in general, that the omission of soy seems very much a noteworthy thing. And yet it's not presented as that, in this case. Rather, it's simply a matter of taste. Soy doesn't work well with coffee, so it will not be offered.
Naturally, some people were offended by that notion. And I can't imagine such a move playing well in any cafe I've ever worked.
There are those who prefer the taste, and on that subject, I can hardly say they're incorrect. There is a certain subjectivity to that sensory experience that can't be denied. And yet, even trying to be objective, I feel that there is the matter of quality, that actual milk might be tangibly superior to soy. Certainly, it's more traditional; but that alone isn't sufficient justification. So no, as much as I might like to, I don't think I can say that actual dairy tastes better than soy, with or without coffee. There just isn't a way to measure it.
That brings me to the health argument. You'll not find a more controversial food than milk -- except, perhaps, soy. Both are held up as near panaceas, perfect proteins that build muscle, burn fat, cure cancer, etc. But both are also hormone destroying killers as well, depending on who you listen to. So who's right. Well, I am. Or more accurately, the research is. Despite what the vegan armada would have you believe, lactose tolerant persons have no reason to avoid dairy. In fact, people probably should consume more of it. The protein in milk is isolated and sold as supplements, as is conjugated linoleic acid, a fatty acid found in milk. Dairy is also high in stearic acid, a saturated fat has numerous document health benefits. This is not to say that soy is nutritionally void, just that it's not the powerhouse that dairy is.
Some drink soy for reasons other than preference, however. They might be lactose intolerant, or allergic to casein or whey. In any case, they have no choice but to avoid dairy. For them, soy can be useful, insofar as it allows a passable latte experience. Of course, some would argue that said latte is not passable, and that the customers would be better off drinking black coffee. I agree with that, for myself. But again, there's no accounting for individual taste, which varies infinitely.
All of this presumes that soy's quality matters, to an extent. Perhaps it's irrelevant that soy may or may not ruin coffee, or that it may or may not spike estrogen levels (it doesn't). Maybe all that matters is that some customers are going to want it, therefore coffee bars ought to have it. Nice as that sounds, it doesn't logically follow. A customer might well like a great many things, all of which no coffee bar can accommodate. They might want a pancake flavored syrup, and we may not have that. True, if the shop down the road does, we may lose that customer. But that's the vote of the market -- the only vote that really counts in business.