Nope. There is neither a moral nor a legal obligation by anyone to talk to anyone else. As it makes no sense your asking me this, I must assume I blocked someone and you want to know why. I block people when they waste my time, when they troll me, when they insult me, or when I have explained something several times, and they don't let it go

On a few occasion, people have emailed me at my website and asked to be reinstated. If they commit to not doing it agai, I will .

That said, no writer is obligated, either morally or legally, to spend their time debating a reader