Yes a moderator can close a question unilaterally. That is why they have the ability to do it.
Closing this particular question was correct and I too would have voted to close it because of any of the following reasons:
The question is too broad. There are five questions bundled into a single post. Questions on the site should be focused and should consist of only one indivisible question per post. This aids in creating proper detailed answers and also aids in organizing and consuming information from the site.
The questions feel rhetorical, it is apparent that the intent is not to gain information but rather to make a statement and to argue, the statements being:
- Most terrorists are Muslims
- Muslims are leaving Islam
- The whole world is suffering because of Muslims
- Muslims emphasize on forceful conversion
- Anyone can convert to Islam (?)
This is further supported by the provocative comments posted by the questioner:
Actually I am spreading awareness.
If Jihadi will not be human, they will responsible for eradication of entire muslim, although muslims are more but not powerful like jews, hindu etc. So be conscious otherwise you know what will be result.
This is not the sort of content that we want on the site.
The question are off-topic because they not about the teachings of Islam. Only those questions are entertained which ask about 'what Islam teaches'. Whether most terrorists are Muslims or why most terrorists are Muslims is not a question about Islam.
I have taken some time to research the question and write the answer. I feel my time is wasted for answering the question.
This isn't anyone's fault. If you see a poor question that does not fit the site then ignore it, leave a comment explaining why it is not suited for the site, downvote it and mark it for closure. We do not want irrelevant content on the site. I disagree with temporarily opening the question just so that a single individual can feel that his effort is not wasted - controlling the quality of content on the site is more important than your time. You are free to post your response to a chat room or a discussion forum or a blog or any social media platform which accepts it.