(Rant mode on)
Seriously -- WTF, Google? Google Contacts is perhaps the most unusable piece of software I am forced to use, and it exemplifies everything that's wrong with Google as a company. They forced me into this idiotic "Contacts Preview" UI, and years later it still fails to fulfill the most basic functions of a contact list.
(Yes, I could abandon Google Contacts -- all I have to do is abandon Gmail. Suffice it to say, that's a tall order at this point, although I may eventually be pushed into it.)
The one that always burns my butt (which I just hit again, which inspired this particular rant) is the fact that there is no way to say which email address to use for someone in a group. Google loves nothing more than to combine your contacts, so that instead of having four contacts for four email addresses, you have one contact with four email addresses. But you don't put an email address into a group, you put a contact into a group, and AFAICT there is absolutely no way to say which email address you want for this particular group.
My impression is that it simply always uses the first-listed email address for that contact. But AFAICT there is no way to re-order the email addresses, short of erasing and retyping them! (And of course, in typical Google fashion, they completely ignore the fact that different groups might be different contexts, and call for different email addresses.)
About every six months, some recruiter from Google tries to lure me in. I try to be polite, but this sort of crass incompetence keeps leaving me feeling like I would never want to work for a company that would put up with nonsense like this. They're the anti-Apple: as far as I can tell, they simply don't care about the user experience enough to put the slightest damned effort into it. As far as I can tell, I would find working there to be incredibly demoralizing.
(Or, I suspect more precisely: they don't care enough unless their corporate case of ADD has latched onto this topic right now. In which case it gets huge attention until the company gets bored, and wanders off to pay attention to the latest shiny, dropping all effort to make the existing software function right.)
Folks constantly ask me whether they can trust Querki, which after all is a much smaller company than Google. This is my heartfelt rebuttal: while my resources may be slim, I care passionately about making Querki as good as it can be, and supporting the users. I don't think you can say that about Google for any products except search and advertising. Everything else is just another Technology Preview, to be pushed for a little while and then abandoned.
(Rant mode off)
As to the question at hand, I eventually found this article. The secret turns out to be contained in the comments down there: if you scroll the left-hand bar way down, and open "More", you can abandon the goddamn Google Contacts "Preview" (never mind that it's been the status quo for years), and go back to the old, ugly but actually functional Gmail-style Contacts. That UI actually works -- there is a way (easy to use, although with crappy affordances) to say which email address to use for a given group for a given Contact.
Which I guess just underscores the point. Google got distracted by a New! Shiny! UI!, pushed everyone into it, and then lost interest and never actually finished it. So the old UI is still hanging around, for those of us who care more about a product that works than one that follows the latest visual-design guidelines...