Are you basically just referring to answers which are nothing more than a code snippet or a simple command? Or even just a single link to another site/article/etc. with no explanation or context?
Indeed, these are bad answers. They may solve the problem for the OP. They may help people in general. And for these things, they are appreciated. But they should be improved.
You have a few options, which are not mutually exclusive:
- Down-vote. If you think it's a bad answer, down-voting is the immediate way to address it. That's why the voting system exists. If the user who posted the answer is getting down-votes, he might realize that it's time to come back and fix it. Indeed, this happened to me recently, and the system worked. I got lazy in an answer, it was down-voted (with a helpful comment explaining why), I fixed it (and left a comment to indicate that), and the down-vote was removed.
- Leave a comment. This happens a lot on Stack Overflow. A user will post a lazy answer and someone will leave a comment saying something like, "Maybe you can explain a little bit about what this means or why it works?" Sometimes the answer gets fixed, sometimes it doesn't.
- Fix the answer. You can edit the answer yourself. All content posted here belongs to the community, not to the person who originally posted it. If you can improve an answer, please do so. (The community and/or moderators can always reject edits, roll back edits, lock posts, etc.) It often feels a little awkward to edit someone else's answer, but it shouldn't. It's perfectly acceptable behavior.
- Flag for moderator attention. If the content is so bad, if it's unfixable, if you have reason to believe that it simply just doesn't belong here, flag it. You can always use the "other" flag reason and indicate to the moderator team why you think the answer should just be removed. (Note that this doesn't necessarily apply to incorrect answers, since moderators can't be expected to be experts in every subject, but just to bad answers.)
- Answer it yourself. You can always post a "competing" answer. This is especially applicable if, as @RobHruska points out in a comment below, an edit to the existing answer is rejected. Don't "poach" the existing answer, of course. But if you can reasonably post similar content but include more information about that content, then do so. Ideally, over time your better answer should bubble to the top and the worse (albeit potentially correct) answer should sink to the bottom.