The question mentions these two concerns:
Closing questions is something seen as "unfriendly", which seems to be the buzzword of the year. Downvoting poor questions or answers is also seen as "unfriendly".
If I understand, part of the problem is that users who do what is required to make the site useful are blamed for unfriendliness. That creates a difficult choice - don't do what has made the site work, or do it and get criticized for it.
One approach - not a comprehensive solution my any means - is to reduce the conflict between downvoting and friendliness. In other words, make downvoting friendlier.
New users are given plenty of help to ask good questions, but still ask low quality questions. Obviously some (many? most?) users do this because they just don't care. But there are also a lot of users who just don't get it. They think they're asking good questions, they're not, and they're frustrated by the response. They incorrectly conclude that other users of the site are hostile.
One way to mitigate - not solve - that is for users who downvote to keep doing exactly what they are doing, while tweaking what new users see and experience when their questions are downvoted. This is not a suggestion that we add comments with downvotes. It doesn't involve any new behaviors or requirements for anyone who downvotes.
My specific suggestion: When a user's question is downvoted, show them - and only them - a generalized message explaining why questions get downvoted. Remind them of the same things they were told before they asked the question. And emphasize that it's not personal.
Do those users even realize that if they've asked a low quality, downvoted question, that they can delete it and restore their reputation? Do they realize that they should? Think of what that would communicate:
We don't want you to have a low reputation because you asked a low-quality question. We want you to deletefix it yourself.
One could make a giant list of the problems this would not solve and the types of users whose behavior would not change. But there are significant number of users who just don't get it, and the way the response appears to them is more likely to make them angry than to encourage them to improve.
I'm not saying they should be angry or frustrated. It's just human nature, and there's a way to help them to respond more rationally and less emotionally. It's technically easy to implement, and it places zero burden on anyone who downvotes. It might even make downvoting easier. I don't downvote nearly enough. I'm imbalanced toward seeming nice, even though I know it's not what's best for the site or even the user who asked the question.
It's not a cure-all, but I'm 100% certain it would yield productive results in at least some cases. And it's simple, low-risk, and doesn't make anyone do anything they aren't already doing.
It might also be fitting for new users' downvoted answers.
Edit: I previously suggested encouraging users to delete their downvotes questions, which apparently doesn't help - they still get banned. I edited that, but shouldn't users with downvoted questions be encouraged to delete them? Isn't that pretty much the same thing someone else will have to do anyway? Is someone who deletes their own low quality question the same as someone who "pollutes" with bad questions and needs to be banned?