I don't think any author has to respond to feedback, but it's always seemed the polite thing to do.

*nods* Yeah, I'm not saying I'm immune to getting a reply from author, especially if it is more than a simple thank you.
Ensuing discussions are fun - and often reveal more of the story's and characters' background, etc -in some cases even additional plot, you know? I love those, pressing on thread links and learning more. But if it is not author's cup of tea I am not hold it against them, which seems to be the case with some.

What I am afraid of is that that hate memes only hurt people and as a result of that make them go away -- which is less fun for everyone who were enjoying the work of that author!