Well, unfortunately it can happen, although not really often.
The background is in most cases, that there is a common misconception, or an unsaid ideological reason around the topic. And the answers are regularly racing to formulate this common misconception, or they are racing to express their opinion in the possible clearest and most obvious form.
What you can do: the rules are very clear. If you think an answer is bad, you are free to downvote it - and express your advices/suggestions to the answerer. If all of the answers are bad, then you are safe to do the same with all of the answers. Maybe it is a litte bit confrontative, but if you are sure, this is what you had to do.
Of course a very polite communication is in this case highly suggested. Getting a down isn't a pleasant experience, so be clear, rational, and polite, even if you don't get this back. Consider: the people getting the downvotes don't think they are wrong, they think (at least, initially) that you are wrong.
If there is an unsaid ideological reason in the topic, try to avoid this, and focus only to the factual aspect of the problem.
I would also highly suggest to use references to support your viewpoint, to make your arguments much more believable.
And, of course, answer your own version, too.
The result will be probably, that you get some downs to your answer, and you also lose some reputation by your initial downvotes. Probably you won't convince everybody on the spot :-), but your answer will serve as a lighthouse. Now, and in the future, you will probably get some upvotes back from people agreeing your version, and it will compensate the lost reputation. Don't forget: an upvote is five times stronger as a down, at least in the sense of the reputation.
If you need to do this too often, then you aren't probably on a really usable site. On my opinion, SF is not on this level, from a factual view it is relatively okay.