The most upvoted answer to this question, Who owns the copy if a copywriter provides copy as a paid service?, gives advice (ask a lawyer) rather than answering the question (what are the terms of a work for hire arrangement). As a QA site, our purpose is not to provide advice on individual cases, but to provide answers to questions that may be useful to others.
Someone embroiled in the middle of a legal dispute probably should consult a lawyer to be sure of their rights, at least if they can't negotiate a settlement on reasonable terms. But writers have a legitimate interest in the rule of ownership when it comes to freelance work that they should not have to ask a lawyer to discover.
Wikipedia has a good article spelling out the definition of work for hire arrangements. The reason questions like this one matter, though, is that if you don't know the term "work for hire" you don't know how to look for that article. Many different ways of asking for the same question are still legitimately different questions. An answer that give a brief explanation of work for hire and pointed to a more complete source for details could be useful to many writers not currently involved in legal disputes who happened to phrase their question in the same way.
So, the answer in question should clearly be a comment, since it is not an answer and an answer would clearly be useful. Those who are upvoting it are presumably doing so because they think it is good advice in the particular case, not because they think it is a good answer to the actual question that was asked.
But this is by no means to the only case in which people have given advice rather than strictly answering the question asked. Many questions in the form of "How do I do X" get answers in the form "You probably should not do X at all." Often such answers are highly upvoted or accepted. In many of these cases, I think the "don't do that" answers are in fact legitimately general advice for anyone who may be asking that question, rather than addressing the individual case, as in the case of the question cited above.
Still, it brings up the question of where the line should be drawn? When should a non answer that nevertheless gives legitimate advice on the individual case be demoted to a comment, even if it is the most highly rated answer?