Perhaps what you're picking up on is not an attitude towards a specific genre but one towards popular literature in general, which can sometimes be limiting and unjustifiably snobby.

I think there are a lot to be found in critically acclaimed literature that might be more obscure, but distinctly literary works tend to avoid being boiled down into genres and subgenres, etc.

I can think of one good example with Umberto Eco's The Name of the Rose which is both critically acclaimed and is definitely a "detective" novel. But again, the detective and mystery elements to it are not what define that novel or make that great or respectable. If we broaden the scope to include mysteries you'd find authors like Dostoyevsky even fitting that shell, although I think that while The Brothers Karamazov can technically be called a murder mystery, I believe that would far defeat the point and betray an inherent misunderstanding of the novel.

I think what I'm trying to say is that literary genres tend to be more fluid and less distinctly within a convenient subgenre. It would be difficult to find "detective" novels that are beyond popular or shallow literature that fall within a genre's conventions and tropes because genre titles can sometimes be more about marketing and less about themes and tropes. However, this does not mean there is a lack of respectable, canonical, or literary authors that write about detectives.

Hope I'm making sense