I disagree.

If it's going to be a detective story with some sex in it, I expect it to lead with exposition, plot points, and character development related to the detective story. I expect the sex scenes to be introduced later, organically, as the story develops. And I expect a story that is presented as a detective story to follow this pattern.

On the other hand, if it's going to be a sex story with some detection in it, I expect it to lead with sex scenes, etc. And I expect it to be presented as a sex story.

I don't think it's judging a book that's presented as a detective story to instead open like a sex story. That's a bait-and-switch, in my opinion. And a weird one, too.