The users of GD are not a homogeneous group, we disagree on a lot of things. There is no council, no secret society, no guaranteed consensus. We learn from each other, we sometimes ignore each other. GD - as any online collection of people - changes both in individuals, culture, tone and use. Leading by example, I think, is the only way to alter things.
I would be delighted to see some exact examples of how we can do better. Personally, I do not see the problem in my welcome-comments, though it seems my comment has triggered some discussion. Having said that, I came from StackOverflow, and if you dare ask something there, it is quite normal to have fifty people piss on your question within half an hour. Compared to that, GD is a delightful walk through the tulips.
Here is how it works for me:
In the review queue I get a "first post" review or "low quality posts".
This could be a first post or first answer from a new user
- I read the question/answer
- I read the answer/question
I write "welcome to GD" followed by what I think is constructive. I recognise there is a fine balance. If my comments are considered rude, I would like to know why, and what I could do better. Here are the general welcome comments I use:
New users post lacking informative images:
Hi there, and welcome to GD! It would be most helpful if you could add
some screenshots and show us what you have tried and where exactly you
get stuck. This saves everybody time, and makes it more likely that
you will get helpful answers.
New user font-id question:
Hi there and welcome to GD! We have a collection of font
identification resources, and it is a good idea to try that first.
Edit your question and let us know what you have tried without luck.
Always good to show a little effort, and chances of getting a good
answer increases.
https://graphicdesign.stackexchange.com/tags/font-identification/info
User (new or not) lacking helpful images
Greetings! It would be of great help to us all if you edited your
question to include some images. Saves everyone time, and increases
the chances that you will get a good answer.
Not actually an answer
Hi there, and welcome to GD! This does not answer the question, and
are better suited for the comments-field. Your post will most likely
be removed for that reason, unless you edit it to actually address the
question.
The last one, I have altered recently to be:
Hi there, and welcome to GD! This does not really answer the question,
and are better suited for the comments-field. Your post will most
likely be removed for that reason, but you can edit it to address the
question if you like. Do not let that stop you from participating; we
know that using this site is a learning curve.
Then if relevant, I alter them slightly if suitable.
I try to be consistent in pointing out to new users that they can edit their questions or answers, that is extremely important information that will help everybody.
I fail to see how to make this more constructive. I could of course write a purely "welcome, nice to see you" without anything else, and then hope that someone else will ask for the information needed to answer the Q. To me, this is inefficient and unnecessary.
The best way, I think, of changing a "culture" is to lead by example.
Edit:
To me, the alternative to these comments would be vote to close with no explanation, no comment at all. That is not nice.
Another thing: there are other ways of leading by example. Long strings in comments and chat, more or less aggressively demanding welcome-ness without concrete examples is not constructive and not nice reading for new users.
When I first came to GD, I was delighted that someone said "welcome - please provide...".
Here is another way to lead by example. I have never seen you voting in reviews, I can only assume you have not checked what privileges you have.
"I am not a mod"
is not true: you are. As are we all.
In your profile page there is a link called privileges
. This will show you what moderating tools you have and where you can help shape this site by voting. Currently you have these privileges:

By clicking review
in your toolbar, you can help by leading by example.