I think mehow's answer explain the general situation very well, so I'm not going to revisit anything there. But given your most recent question, I think I've finally figured out what the whole purpose of this is feature request is.
You believe that the presence of an accept answer somehow changes whether the feature would get implemented or not, so if a feature request has an accepted answer that somehow says that the feature isn't necessary then it means it won't get done. That is absolutely not the case, especially when the individual is not speaking for Stack Exchange, Inc. (the employees usually have diamonds just like moderators, but their profile will indicate that they are employees). In fact there is an answer from an employee and he says nothing that suggests it won't get done (or will get done - so it is still up in the air).
An appropriate status tag (usually status-completed, status-declined, status-review, but there are others) usually indicate the intentions of SE and until then the feature is still open and subject to consideration. And even then, there have been cases where features were previously declined and have still been implemented. If you want to attract attention to a feature because you think it would be beneficial, then you have 3 options:
- Add your own answer an explain why it would be useful
- Add a bounty to the question to attract new attention too it.
- In some very limited cases, asking a new question might be appropriate, however you shouldn't do it unless you are sure your question is not really a duplicate. And just because an old feature request does not have an answer doesn't mean you should ask a new question. On meta sites, old questions without answers can still be duplicate targets.
It is unnecessary to "downvote the acceptance" or, in most cases, to ask a new question if you just want to revisit and draw attention to an old feature question.
The reason asking a new question is usually not a good idea is you end up hurting your own cause. There are 12,000+ open feature requests, so new questions only cause posts to get lost in the mass of feature requests. Plus duplicates only serve to split the discussion and make it more difficult to assess community support, which will only make it harder to decide if it is worth pursuing a specific feature.
However, it is easy to understand why this might have been confusing, and also why some users try to discourage accepting answers to true feature requests unless there is some indication by the SE staff that the feature will or won't get done for that reason.