The initial idea of banning homework so that people don't use this site as course help has been long outdated as there are many other sites which can give provide help of that sort
This is a strawman argument. The reason we don't want homework questions here is not because we think it will keep people from cheating on their homework and think they'll give up if they can't find it here.
There are several reasons that different people don't want homework questions here. The most salient to me is that the front page being filled with homework questions makes it difficult to find questions I actually find interesting. What's worse is that this may drive off the kind of users that want interesting physics questions instead of homework question after homework question.
Mathematics SE's policy means their front page is absolutely inundated with homework questions. At a glance, it is currently close to 50% blatant homework questions.
As you say, if you want a homework help site there are plenty on the internet. Why would we want to become another one?