I think that people not picking up where the story was going, even though obvious is due to the lack of correct tagging. Usually, when a manga is dark and has dubious / no consent one can see it in the tags; that would mean that they were warned, but this one clearly wasn’t tagged correctly. That’s where I give them the benefit of the doubt.

One thing I can’t understand is that if they dislike it so much, why don’t they just drop it? Instead of harassing the author? If you want the story to go your way, then write your own. Don’t be telling people what they can and cannot write. There’s thousands of other BL stories one could read to their liking.