Incentives for Answering Low-Quality Questions
The linked question is a low-quality question. It doesn't "show research effort" nor is it "useful and clear." It was tagged for closure days ago, but on PMSE we tend to give people a fairly long tail before actually closing a question.
As for answers, Stack Exchange incentivizes providing answers more than voting, and perversely incentivizes early answers on close targets because closed questions don't allow competition among answers after the closure. This has been discussed for years on meta. Quite simply, you can gain reputation with great answers (or even mediocre answers) to low-quality questions, and closed but undeleted questions provide little incentive to downvote the questions or answers. As a result, it generally behooves people to answer questions whether or not the question is a good one, and whether or not the question is ultimately closed.
The only way to change this behavior is to increase the deletion rate of questions, and we've generally had a policy of closing (but not deleting) bad questions with upvoted answers. You get what you measure, so as long as people can gain reputation from answering questions rather than voting on them, the behavior will continue.
