You are entitled to your feeling, never said that your struggle was invalid. But my point was not that all people have been good to me therefore I don't see the problem because we are all a happy family over here. I have gotten exactly what you are describing, I'm not kidding, all of the comments you describe, (except the art theft! That's pure evil).
For normal/average commentators I believe that you contribute to the way people interact with you with by setting the tone of your own interaction. You say that you are not mad at them for not talking exactly what you want them to, but it still think you are having expectations over something you can't control. You ask if it is unreasonable to ask for people not harass you and that they talk about other stuff like ship that don't exist, off topic stuff... if we simplify it like that then, yeah in a way is unreasonable. Because you don't control how people react, they are not in your head you are not in their head, they might not even be aware that you want feedback.
About the harassment, that's abnormal interaction, it is rude of them, it is despicable, but the bottom line is that you can't control them either, there are so many horrible people with access to the internet. You can block them (if it is allowed) but they exist everywhere. The more popular you get, the more you get those people because they are already there waiting for something to obsess over. If you can block them, the better, maybe your own fans can help you report the art theft or at least go there and post a comment about that stuff being yours. And when that one gets away other troll will take their place! They never stop being annoying but they are unfortunately a part of the "internet fame".
I'm personally never bothered at all about unrelated comments, totally off topic remarks, etc. But I totally understand why you expect people to react to the art you have been making for hours of hard work instead of random stuff in their head, but the reality is that most readers are not creators and most of them are not even aware of how to even give a proper comment or feedback. It it bothers you that much, try to ask nicely "hey! I would love to hear more about this and that please, because I want to improve this and that." We have established that some commentators might not have an art background or don't know how to express themselves, then you can ask specific things about the shading, about the pose, one simple thing at the time so that they don't have to feel overwhelmed. Yes, you can directly encourage them to give some type of comments! I understand why you struggle, and as you grow an audience this is not getting better because we are talking about a third party we can't control. Maybe you expectations can be more flexible for your own meant peace.
