In short, Answers need supporting explanation, not just one-liners.
From the Help Center (emphasis mine):
Read the question carefully. What, specifically, is the question asking for? Make sure your answer provides that – or a viable alternative. The answer can be “don’t do that”, but it should also include “try this instead”. Any answer that gets the asker going in the right direction is helpful, but do try to mention any limitations, assumptions or simplifications in your answer. Brevity is acceptable, but fuller explanations are better.
And from our Back it Up Guideline here and here:
Please note that answers should be backed up either with a reference, or experiences that happened to you personally. You should always include in your answer information about why you think your answer is correct.
One (now deleted) comment on Kilisi's post got a lot of attention:
since meta comments under the answer were cleaned up, here is my copy of comment you referred: 'without an explanation, this answer may become useless in case if someone else posts an opposite opinion. For example, if someone posts a claim like "Don't refer him to your manager. Much positive is in this for you.", how would this answer help reader to pick of two opposing opinions? Consider editing it into a better shape, to meet How to Answer guidelines' (and this is example screen shot I also referred in there) - gnat
The reversal is a little forced IMO - a better counter is probably "Go ahead and send it to him. You have nothing to lose." In any case, his point still remains. If someone else came and posted a contradictory answer, there would be no way for users to reason which answer is better. The argument is always made that the votes will decide for you, but that doesn't help if not many people vote, or if the answers are controversial and both garner similar number of votes.
This site shouldn't be just about answering single questions, but also about giving users a better understanding of how to approach future scenarios. Another user may come along and have a similar but slightly different situation. With no explanation, they can't really understand why one answer is better than another and know how to apply that reasoning to their own situation. Then, they will ask their own question and have it closed as a duplicate because it was already asked and answered, just not in a way that is useful to anyone else.