Low quality answers have become a significant problem on this site. This is a problem that needs to be addressed, but the moderators are getting very little in the way of policy feedback from the user community. In the absence of community based policy, the moderators are falling back on standard SE policies as the default, and standard SE policies are to delete low quality answers.
Let me clarify something. "Low quality answers" has a fairly specific meaning in SE and is not to be confused with "answers that aren't as useful to me" or even "answers that I think are wrong". A quality answer is clear, specific, and detailed. A one sentence answer may be clear and specific, but is not detailed, and that makes it low quality.
Why this matters: Quality answers are resources for future visitors, they provide helpful information that a searcher may not even have realized they were looking for. Usefulness to future visitors is one of the reasons why SE works. One sentence answers help only the original poster.
So, if this community wants to be a serious SE site, we need to improve the quality of the answers that we are getting. To do that, we have to enforce quality standards - and one sentence answers just won't cut it.