Stack Overflow Without the Cancer?

Marking questions as "stupid, irrelevant, lazy etc" is SO's way of maintaining site content quality. Though they do get a bit aggressive at times, it's actually a good thing. A site without that just turns into Reddit.

AKA Shitpost Central.

AFAIK there isn't one and is not really an issue of platform or technology. In my opinion even if such a site were created it would devolve quickly into everything negative that you mentioned unless it has a solid team of great moderators, architects and leaders that understand human nature thus designing around it. HN is an example of a well moderated site, but it is a simple site relatively speaking. Stack Overflow could be everything you desired but was not guided in that direction. From my experience editing posts on one of their groups it was expected to just grow organically without external intervention. I assume this was to make a big knowledge base platform with low overhead by outsourcing all editing to volunteers that would eventually be acquired for a nice sum of money. I expect some day people will need a paid account to access answers, but that is the cynical side of me. I have never seen a large complex site like SO designed with human nature factored in but would love to see one.

Hire a consultant. It doesn't scale and is expensive. So, it ain't for everyone, obviously, of course.

Like Wikipedia, StackOverflow mostly does what it must do to be a better alternative than anything else.

If StackOverflow did not close questions the way it does, pages would be (more) full of answers that call the person asking stupid, lazy, etc.

StackOverflow is not designed to protect itself from the people asking questions. It is designed to protect itself from the people answering them. It is designed to discourage social dominance. Discourage an insider versus outsider culture.

Yes it has rules and norms. Like all rules and norms, they are not for everyone. Unlike most rules and norms, they are not established to further entrench entrenched power (yes, there's a first mover points advantage to answering a regular problem but there's a low cap on the maximum required points for trust advantages).

To put it another way, StackOverflow is designed to minimize the effects of the bad ways people behave. It cannot eliminate them. Good luck.

what kind of questions are you looking to pose? you could try https://sqwok.im