I understand what you're saying, but there are a few issues with this:

1. There are many accounts exactly to the opposite, non-US citizens having traveled to and from the US for decades without this level of questioning. If there is a policy change, then it should be clear to travelers; such a change doesn't just affect non-citizens, citizens working to bring in employees, guest lecturers, business associates, etc, are made to look foolish as well when they can't arrange the meeting. They don't have to publish the questions at all, but there should be some guarantee that the CBP is actually qualified to judge the answers.

2. Most of this should be done by the consular at the embassy when you apply for the visa, well before you even get to the border. CBP guards see dozens of persons each day with a wide breadth of employment backgrounds - is it really required by these guards to be that knowledgable in so many subjects to perform their duties? Or is it arbitrary checks based on what the guard themselves knows? The contention with this is that no one knows what the actual policy is, so it's hard to say whether or not the guards are doing checks they're supposed to be doing or if the guard even has the requisite knowledge themselves to judge a yes/no of an answer. A questionnaire for professions is equally troubling since, as many can recount with recruiters marking perfectly sound answer as "wrong" because the answers weren't what was written on the sheet, or the recruiter didn't understand the answer.

3. Some of the criteria are really strange for using to judge whether or not someone is telling the truth - the qualifier mentioned elsewhere in the discussion about asking someone's wife what her husband worked on seems pretty asinine; how many people from the DC area tell their spouses by requirement they work for the DoD and nothing more? How many contractors that land a government contract are 100% open with their spouses about what they work on? Certainly other governments have similar restrictions and NDAs for their employees/contractors. Or even once you start to get into specialized topics, how much can your spouse really understand about what you're doing if they're not in the same field? For a simple example, I work in just IT support, and my partner is fairly computer illiterate. If pressed, she probably could tell someone I work with databases, but not much beyond that, even though I've explained what I do at her request multiple times. I get there can be levels of validation here (does she at least confirm he's a programmer), but the validity of such a test question really depends on a lot of variables, and the value judgement of "how much should they know" will change drastically depending on very common circumstances.

People are quick to pin this on the Trump Administration because it is taking a very hard stance towards immigration and not addressing the issue at hand. While it may be individual guards being emboldened into getting this aggressive, the question becomes why is the administration not making a statement on it? Why has the CBP not made a statement one way or another on whether these are legitimate actions? With the EU planning to end free-travel for US citizens and the Trump Administration trying to play hardball with the deal, it's pretty easy to wonder why the current administration isn't dealing with something that a lot of people find to be ridiculous and wrong. With a president that is willing to tweet and comment about celebrity impersonations and individual news stories, it seems strange that they'd turn a blind eye to something that has a major impact on US relations with the entire rest of the world, especially since there are numbers to show that interest in US travel is declining.

As a final aside, international flights, especially trans-atlantic, can be pretty rough on sleep schedules and just in general. I just went from St. Petersburg Russia to Seoul, and I'm not sure that I'd be able to answer difficult questions about my profession on the spot without some time or resources. It's pretty bizarre too since entering Korea took about 30 seconds at the passport control. I'm a US citizen and I haven't even been able to enter the US that quickly in all my travels.