If you post something here and ask for feedback, that's what you're going to get. It may not be what you were hoping to hear, but it will be an
honest reader's reaction. And with unpublished work, that is exactly what you want. That's what is the most helpful. And the best part is you can
keep posting it, after you've worked on the issues a bit, and we'll keep reading it and continue to help you improve it. There is no place I know of where this happens simply because the members of a site WANT to help each other.
That being said, no one is obligated to change anything based on feedback. It's your story, after all. And feedback here, just like a review of published work, are only opinions. You can take them or leave them.
I've had feedback on unpublished work, and reviews on published work, that have left me scratching my head. And sometimes, the author giving feedback on unpublished work has ideas about craft issues that are wrong, I'm sorry to say. Probably because they learned it the wrong way. What constitutes passive voice seems to be a biggie for this, though I'm not sure why, since it's fairly straightforward.
In those cases, and in cases where I'm left wondering if the reviewer actually read the same book I wrote, I take what's useful and leave the rest. My litmus test for any type of feedback or review is that if I'm reading the same thing from several people, I need to sit up and pay attention.
If, however, it's an isolated issue or something so off the wall I'm unable to figure out where it came from, I move on.
I once had a reviewer say she "threw up in her mouth a little" at my choice of a certain word she hates. What a silly, juvenile thing to write in a review,
especially a reviewer who is known to read the most graphic, detailed BDSM books and LOVE them to bits. LOL!
Gotta have super thick skin in this game. You have to be able to laugh at stuff like that, while also taking constructive criticism.