Our stated purpose does not say that answering homework questions is okay. The closest I can come to that conclusion that that LSE is for students... and others. The on-topic list is silent on the matter.
As a teacher, I have a strong negative reaction to websites that sell homework solutions, and an even strong one to ones that give homework answers away. The leading answer here agrees that homework questions (of the form "do my homework") should be closed. Official close-reasons and how they gained that status is deep read-only arcana. Since in fact SE includes an open-ended "other" reason for closing (which was invoked in this case!) the fact that "do my homework" is not on the officially-enumerated list simply means that it's not a pre-set button: it's still a valid reason to close.
Speaking only mildly in favor of allowing homework solutions, such questions do at least serve the function of providing general answers applicable to multiple situations.
Speaking more against allowing homework solutions, I disagree with the premise that a person bears no moral responsibility if they know or should know that they are enabling an immoral act – unless one is giving legal advice, which of course nobody here is doing. You might imagine that a student is eliciting answers to homework questions and then fully citing the answers including LSE URLs: I see no evidence for believing that that is how individuals plan to use such answers. I don't deny that one can imagine there being a possible scenario where answering such questions is not pandering to the worst elements of society, I just don't have a reason to assign honorable motives to such questions.