Here is the link to the recent statement by the American Psychiatric Association President drawing attention to the so-called “Goldwater Rule”:
On occasion psychiatrists are asked for an opinion about an individual who is in the light of public attention or who has disclosed information about himself/herself through public media. In such circumstances, a psychiatrist may share with the public his or her expertise about psychiatric issues in general. However, it is unethical for a psychiatrist to offer a professional opinion unless he or she has conducted an examination and has been granted proper authorization for such a statement. (Bold added.)
Interestingly, the Washington Post puts it this way:
The short version: It’s okay to talk about psychiatric issues — but not okay to diagnose people you haven’t treated.
Of course, there is a lot of daylight between “shar[ing] with the public . . . expertise about psychiatric issues in general” and “offer[ing] a pofessional opinion.” Most of that uncertainty derives from the wiggle room in the phrase “in general.” Note also that the Post short version above does not include the qualification, and I have to feel that the Post article overall, while quoting extensively, feels less restrictive than the APA statement.
In any event, I note that there is a lot of parallel with our issues about legal information. I would suggest that the no opinion from shrinks rule might help us say that the information only rule can seen as simply a “no opinion” rule. In other words, the simple explanation of our rule is “just the facts, m’am.” Of course, some would argue that there are no facts in psychiatry — or law.
As to the practical impact on psychiatrists however, I do recall the lovely line in House of Cards, when the FU character drops a hint, the naive young journalist asks the intended follow-up and FU replies: “Now, you might well think that, but I couldn’t possibly comment.” That phrase has passed into English, at least in English politics.
Richard Zorza's Access to Justice Blog 
The trick is that ordinarily, even “general” statements are only received in “specific” contexts. No one is interested in what a doctor “generally” has to say about an ailment, until they (or perhaps someone famous) might (very specifically) have that ailment. Hence the quandary a librarian could rationally feel in pointing a patron toward a specific resource. Certainly the resource was written without considering the specific person standing in the library, but the librarian now makes the application of the general resource to the specific patron.
I think the test, in whatever the profession, boils down to the nexus between general knowledge and specific people and their specific situations. “Opinion” above only makes sense if it means “opinion about a specific case.” And so, perhaps within objective outer boundaries, it has to be a largely subjective standard, in the understanding of the potential victim. And the best defense (for an information giver who does not want their words to be taken for “professional opinion”) is transparently (and briefly) explaining why they chose to provide this information and not that information.
This all means is that it will be easier and safer to use our words (whatever our professional role) to help the specific person in front of us, though perhaps harder to provide commentary for the media. That is probably a good thing.