> Is it an intentional choice to communicate like this, is it lack of some skill (on theirs or on my part) or something else?
The short answer here is that other people are not you, and by default they communicate to you in the manner they wish to be communicated to. This is a mistake.
Your problem is broad enough that there's a myriad of explanations, but I will narrow and rephrase it as "other people don't answer my questions as directly and succinctly as I expect."
Phrased like that, you can see there's two parts of the equation: other people, but also you. Manager Tools[1] uses a DISC model that I think works well here -- so lets analyze this interpersonal business relationship with it. it's not quite the "big 5" model that psych researchers use but pretty close[2]. It offers 2 dimensions to model personality, and labels for each extreme:
D – Dominance: the tendency to exert power and assertiveness
I – Influence: the tendency to assert oneself socially and interpersonally
S – Steadiness: the tendency to engage in reserved and personable behavior
C – Conscientiousness: the tendency to be reserved and analytical.
Within that model, you land on one of those labels to some degree, and your conversant does as well. Based on your question, I will put you down as a D. You want short and concise answers, and are probably already pissed at how long this answer is. Assuming you are even still reading.
But your conversant isn't a high D. Engineering personalities tend to cluster around Conscientiousness. They want to know the answer and understand the details behind it, and probe the logic for weakness. When asked a question they provide the details _because when they ask questions they expect to be provided the details_. In fact, they hate off the cuff conversations because they want time to analyze and give a correct and defensible answer. They'd much rather write an email with charts and graphs, or at least a two by two matrix[3].
So this is fundamentally a mismatch of expectations, and personality preferences. Personality cant usually do a complete 180 but with deliberate practice most people can move their behavior a few points closer to their conversational parter. So its a skill that _all_ of us have to learn, to accommodate others as they wish, rather than how we would want. It's a scenario where the golden rule simply isn't sufficient.
[1]: https://www.manager-tools.com
[2]: DISC doesn't have some of the drawbacks of trying to describe disorders within the model. Seems useful for researchers and practitioners, but dangerous for laypeople if they go wrong.
[3]: yes, DISC is often shown as one https://united-partners.com/how-disc-personality-assessment-...