I'll respond on the premise that you are taking issue with how Answers get framed on the main site (rather than with the Comments that get directed at what some consider "do my homework" posts, though I'm inclined to focus on whether the asker has digested the meaning of their problem, not whether it is any known sense "homework").
Some users do post Answers that are "hints" in the sense that a valid approach is outlined and a sketch is left for interested Readers to fill in. I don't ordinarily take this tack, though I'll point out some Questions are explicitly framed as asking for such "hints" in preference to detailed solutions.
When the approach so offered is evidently not leading past the difficult part of a problem, I'll often recommend that the post should be a Comment rather than an Answer. In a particularly glaring case, e.g. the "hint" merely repeats something that was already pointed out in the Question itself, I will downvote the Answer and likely vote to delete if the post is not self-deleted.
Other than that the system seems to be rather self-policing. For every post offering a "hint" there will be roughly as many (or more) offering detailed solutions. Those who encourage or discourage one or the other kind of Answer express themselves in large part by voting.
