> What is the point of closing the question that is asked, answered, got
> positive reception by users, and has an answer accepted by questioner?

For the same reason you'd close an offtopic question that hadn't been answered yet; because we want the information on this site to be focused, and don't want the site cluttered up with questions about general security topics (for which there are other stack exchange sites where the user will likely get higher quality answers). The more offtopic questions there are, the more they distract from the sites main topic.

> It gives the impression that there are some over zealous folks who may
> have excessive negative views and impertinent to other users by the
> record of their negative votings.

This seems a little unfair; this is often a problem on SE sites, and something we should try to fix if it happens on Tor.SE, but I see no indication that this is what happened here. As far as I can tell, the question really is offtopic.