Q:

Can I try to tell experienced users not to answer bad questions? 

I have recently started using the website and I am trying to do my best with moderation.  I flag questions very often, I edit posts when they can be improved, I have written a few of those "What have you tried?"  comments and so on.  
I know the topic has been discussed here, and forgive me if this is not appropriate as a question, just let me know and I'll delete it. 
I found that previous question very helpful, and it clarified some of my doubts.  I'd like to ask a more specific question, which has only been touched by the previous one. 
Often the people who answer bad posed questions are experienced users, with thousands and thousands of reputation.  I understood these users are trusted and respected on the website.  I often would like to comment on their answer saying "Why are you doing that?!  This question should be closed not answered!"  
I have been told that when a question has accepted answers, it's more unlikely to be closed, even if the question itself, after edits and comments, is awful. 
Would a comment like that be considered rude or somehow bad by the community?  Most of all considering it would come from a relative new user? 
P.S.: I preemptively apologize for possible horrible grammar mistakes. 

A:

I advise against commenting.  As the cacophony of comments in this thread shows, engaging in a dispute with those users doesn't lead anywhere good.  
Downvote and move on.  

A:

As long as your comment is polite, I see no reason why you should not make any appropriate suggestion.  However, if you feel that a question is indeed bad, and you have the requisite reputation, then it might be more appropriate to cast a close vote. 
Note that the reasons that people might have answered that question will vary depending on what you define as a "bad question".   What is defined as a bad question has undergone quite a bit of debate in the last year or so.  One of the more recent reasons to close a question deals with the lack of context. 
Although I am a moderator, what follows is simply my opinion and not necessarily that of the moderation staff. 
There are bad questions and there are good questions that lack context.   I fully agree that bad questions should simply be closed.   However, good questions that lack context are not necessarily bad questions. 
The people who have been on the site a long time, started when there was not a requirement for context.   If a question was interesting, you answered it.  If it seemed like a homework question, you gave a hopefully inspiring hint. 
A year back, I believe due to the uncertainty as to whether questions were homework or not, the homework tag was removed.  In order to close the questions that seemed like homework, questions started being closed for lack of context. 
Don't get me wrong; context can be interesting as well as useful for forming an appropriate answer, or for knowing when a hint is more useful than a full answer.   However, the context of a question may not be of any interest for people who look up that question in the future. 
However, if a question is interesting in itself, and it seems pretty clear that the question is not a homework question, people tend to answer with or without context.  After all, we are here to learn math, not necessarily learn people's backgrounds or what they have been reading.