Hello, if I may offer my two cents: I don’t think people have an issue with the concern you brought up (disrupting sleep to do reviews). What I think happened is that your proposed solution (have wanikani inaccessible during specific AM hours) was so outlandish to many that it entirely derailed the conversation from the initial concern you were trying to address.
Sharing your story online (and for someone else’s sake, at that) was a really brave thing to do. I’m really sorry you have had the experience that you did. Unfortunately, productivity culture has glamorized overworking and constantly pushing oneself to the limit. I hope you have a strong support system of friends and family you can turn to when things get rough 
And lastly, I can tell you were being sincere in your plea to help those who may be sabotaging sleep for kanji (I feel like this is where someone funnier than me would insert an appropriate kanji joke). It’s the internet – discussions get heated and words get exchanged, but then we log out and continue with our lives. You’re going to be okay 