As has been pointed out in the comments, there is a widespread issue with this kind of behaviour across most of the SE sites. The platform is already designed to limit user contribution types to give them all a fair chance to adjust to the norms of the site before engaging fully, which helps more than we usually realise. In theory, we could make new users click through whole pages of examples, explanations, terms or conditions and know with confidence that many wouldn't actually read or understand what's in front of them. Socialised learning is the way forward.
But in the end, it has to begin somewhere, and most often it begins with their own genuine Question, which in many other places on the internet wouldn't be subjected to the type of rigour and critique that we apply on BH.SE. The entry bar is low, and hopefully that encourages fresh contributors to get started with their very first Question or Answer.
So... what can we do to help new users get the best possible start?
1. Write high quality on-topic Questions, Answers and Comments ourselves
As experienced users, we need to do our best to demonstrate a consistent and good quality in our own contributions to the site. New users will use what they see as a baseline for understanding how to contribute, and so it's worth considering the example that we set in each contribution we make to the site.
Often inexperienced users won't spend a lot of time dwelling on the Site Tour and other site guidelines - but they do scroll through Questions, and Answers, and so the higher the quality of contributions they find on any given part of the site, the easier they'll find it to understand what's expected.
At times it can be tempting for newer users to fire off lots of low-quality questions without much obvious research effort, and flood the site with contributions that don't reflect the standards we aspire to. I'd suggest it's always better to aim for quality over quantity, and even when responding to low-quality questions, we need to set a better example by the Answers and Comments that we give.
2. Purposefully welcome new contributors as courteously as possible
"The result is that their Q often gets a gruff comment"
I'm glad you've captured this observation - that's exactly the end of the spectrum we aspire to leave behind. There's a clear enough set of expected behaviour when I think most of us are familiar with, which summarises it well - I think we're typically very good at the be honest part, and don't feel shy about downvoting or commenting when something is incorrect or misleading. However, be nice takes continual effort and restraint, especially when dealing with questions, answers and comments where we see little value.
So no, I disagree that 'gruff comments' are a result of poor questions - the low question quality doesn't cause us to leave poor quality responses. I'd encourage anybody who feels strongly about this issue to take up the mantle of the 'First Post' review queue, which historically has had various neglect issues.