Tomoyuki Hey, tomo...idk why but this is the thing came into my mind after reading about you. Have you ever build the sand castle near beach? If you haven't... try once it's too much fun(age doesn't matter Okay!) and If yes, then... you know the feel of it. Even after knowing castle has to fall/dissolve we did our best to build one. It doesn't matter how unprofessionally we do but we still make our castle stand just for fun of few hours. Doesn't matter how beautifully one build it and better than us... everyone's have to be dissolve in the end. Still we do it again and again. because the joy of making one for ourself is what matters. Nothing else! Like wise, you should also write for yourself , love your own writing and story. Don't get too disrupted by others...just focus on fulfilling your fantasy stories. Those who will like it relate to it will eventually love it. And there will be many who will thing of it as useless, waste of time, crap, unproductive, and what not.... You don't have to take responsibility of fulfilling their expectations at all. It binds you and lock you. Just write what you like.
And the abuse happening to you is not acceptable at all but don't let it disrupt youself imagination and story. Even if you think you're not the best writer and there are still people who are reading your novel that itself means there must be something readers enjoy in your book. I'm a reader as I've seen many stupid people commenting bad but couldn't stop reading. Some are so over the edge that they'll abuse not only the books characters but Author also... they'll complaint all books for not being perfect(as per their fantasy) but so incompetent themselves to write one( perhaps don't have guts or fear of finding haters like themselves) that's why they expect others to fulfill their fantasy. Some. Readers are so comical that they'll bash in one chapter and after 2-3 they'll either priase(smile) or ignore commenting ( don't appreciates)
Only few readers genuinely criticize the work and many will be ignoreing or being dumb. That's why many potential stories were dropped in earlier stages by Author. Hope you won't quite and take it as stepping stone for yourself and let the best come out of you. All the best👍