Okay, I went ahead and posted the chapters in question on here, if any of you want to read it and judge it for yourselves. https://www.writingforums.org/threads/henry-rider-hazing-the-new-guy.169125/
It's a matter of opinion. I do not think it's in any way an overeaction. Again, a matter of opinion. Have you been subjected to serious hazing? It's purpose may be to weed out the weak -- it can also be to weed out anyone who is different, or who too strong and who might be a challenge to the established alpha of the pack. I've been through hazing twice in my life -- one in college, and again in Army Basic Training. Army Basic Training is the ultimate hazing experience (except for Marine Corps Boot Camp). Even under the strict rules etablished by the military, the Marine Corps still occasionally kills trainees. How is that a good thing?
This here is the plot development forum..if you (anyone) want to have a more general discussion about hazing take it to the debate room
Having read it i stand by my original assessment - this is too much for MG... its more YA material (like say the test scenes in divergent where Tris is forced to face her worst fears)... you could write the same basic principals for an MG audience in less visceral tone ... but that might require rewriting the whole book, so you might be better to just embrace the YA (also since you want to be trad published the distinction is largely irrelevant since your publisher will decide which market to target and what needs to be rewritten to suit that market.... for pitch purposes I would suggest just saying that it is MG/YA)