Scope of this answer
This answer only addresses the particular situation that the OP says provoked her question — the lack of advice (in the form of lack of comments) in downvoting and voting to close a previous question, and the reason given for the close votes. Her first sentence implies to me that she considers this to be “not nice” and “mean”. Whether or not this was intended, it is a reasonable interpretation of what was written, and as I was one who downvoted the question I will not let the implication go unchallenged.
That is the limit of my answer. It does not address the general question of the friendliness of this site, nor, because of its scope, does it invite dialogue in the form of comments. Of course, list members are free to make comments, but I will not reply to them. Comments that satisfy the SE criteria of “ask(ing) for clarification or add(ing) more information” will be considered and, if necessary, edits made to this answer. I will not be provoked into replying to comments that I regard as violating the SE code of conduct, but will follow the SE guidelines and flag them to the moderators.
N.B.
Any criticism in this answer is criticism of the arguments of the OP, not a criticism of the OP herself. Any use of words such as “reject” is solely as defence against general remarks which could reflect on me personally as a down-voter and close-voter of the question mentioned. In rebutting arguments it is necessary to maintain that they are incorrect, but this should not be taken personally.
Answer
The term “Be nice” was at one time part of the Code of Conduct, but this has now been replaced by a list of what is regarded as unacceptable behaviour:
- No subtle put-downs or unfriendly language
- No name-calling or personal attacks
- No bigotry
- No harassment
Thus “not being nice” is defined by SE in terms of unacceptable comments, and clearly does not embrace refraining from commenting.
I understand from what is written that by being “mean” the OP means other than unacceptable behaviour as defined by SE: instead she regards it as a “lack of the kindness” in failing to explain the reasons for downvotes and votes to close. Whether or not I have understood her correctly, I think it necessary to make the following point. It has been pointed out numerous times by list members and moderators that some people choose not to provide explanations in comments because of the antagonistic responses they have received from both posters and other list members who have their own definitions of “unfriendly language”. That was why I did not comment on my down/close votes and I resent any suggestion or implication that this behaviour is “mean”.
The other criticism of the votes to close made by myself and another list member was that a question about a technology that could “Harm human body or food” could not be considered a request for “health (not medical) advice”. As this clearly means “if I use it will it harm me?” it seems eminently reasonable to regard it as a request for health advice. I categorically reject the implication that this choice was “a cover when one can’t close for failure to show research.” It was not.