Well, I can't see the deleted question but I can pretty much understand the situation after seeing your question and comments. This is not a proper answer but instead a very long comment in which I would just try to answer your quotes. This will be long but I am sure you won't mind :-)
The question had positive score, both answers had positive score, and
one had been accepted
First of all, don't start beautifying/judging a question/answer with the number of upvotes/downvotes it has got. Read it and then decide for yourself. There are many rep-farmers and mystery users who up-vote low-quality questions/answers or may down-vote good questions/answers. Many times votes are cast due to personal choices and opinions. So using scores to start your question is not a good idea.
I understand the motivation behind closing it (not enough context)
So you understand that the question is a PSQ and from now I'll assume it is because I can't see the question, but it's quite clear from the comment section.
even though I disagree with it (the question generated two different
approaches to the problem, and I thought had a net positive value to
the site). But really it's the deletion I cannot understand at all
Now my question is why do you consider the question to be adding positive value to the site when you know that it's a PSQ? Is it because "it's a good problem that is interesting or hard to solve"? Well, that might be a good reason in general but not according to this site's policies. I think that you are quite an experienced user on this site and you already know quite a bit, but I'll mention it again. This site is for everyone one and for any level of mathematics. A good question or a quality question on this site is a question that shows user's motivation to learn through their research work, thoughts and in the best case scenarios, any type of attempts made to solve the question. If the user doesn't show their motivation for their question, it simply means that they are too lazy to work, or they don't want to learn, they just want others to do their homework, and this is not allowed in MSE or probably any SE.
But what's the discouragement? The asker got an answer to their
The question wasn't meant to be answered at all. The moment you answer a PSQ you should be prepared to get down-voted and possibly deleted. If you can't accept this then I am afraid that you don't understand the policies of this site very well.
It's very possible to answer "homework" questions with hints, and then
the site I believe nets a gain of mathematical content.
No, the site doesn't gain any good content irrespective of how good the question is: if the user is not motivated enough to show context. If you still don't understand look at the flagging statement of MSE below:
This question is missing context or other details: Please
improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level.
I tend to agree with you that deletion has become too aggressive but I
can understand that some folks don't want the site to be a homework
IMO aggressiveness of deletion is actually proper now that is if you compare it with the history of MSE. Previously, there were fewer users and the policies were not enforced aggressively, which was not correct, but then those were the initial stages of the site and users learned and now they (most of them at least) are experienced enough to act according to the site's policies.
I left this site years ago because of how poorly it was managed.
Things don't seem to have improved at all.
If by improvement you are referring to the reduction of aggressiveness towards the deletion of poor posts then you are very wrong, this site is not well suited for poor posts at all.
If I spend a lot of effort in producing a high-quality answer, and
then another user -- with no context but enough rep -- comes along and
The answer is simple don't spend your time answering a PSQ, rather, as you have already asked from us, try to improve the PSQ by motivating the author and once the question has quality with the author's motivation, you may very well post your high-quality answer.
I think the answer went on too long but finally, I would like to say that the site's tough/unfair/harsh (if you consider it like that) policies are for a reason. I can give you a few:
- This is a professional site with countless students, scholars, teachers, professors, Master's candidate, Ph.D. candidates etc. When they are there to invest there precious time and share their knowledge with the asker, why can't the asker be motivated enough to solve their own question? Is that what you want this site to become? Ph.D. teachers solving home-works? You should notices that the services you are getting here for free, you won't find it anywhere even if you pay for it. Hence, please don't take the site for granted. Respect the policies that help maintain discipline and the professionalism. This respect is directly conveyed to everyone who is contributing here.
- If homework/low-quality/PS questions are allowed this site will be no different from countless other discussion forums, where no one bothers about anything and the askers think that they can use the site however they like for completing their homework like it's their birthright. If it happens, you will lose the dedicated people I have mentioned above in my first point.
- As I have mentioned before: The motivation to learn. The website is actually teaching you ways to improve your approach. A first timer doesn't know how this website works but if they are keen to solve their question and learn then they will stick around and take constructive criticism from the down-votes, comments, etc. and keep on improving the post.
This is how I learned and I have been here for just more than 2 months. You have been here for 3 years, I hope you understand better than me.