That's a surprising reaction, especially if he writes back a couple weeks later. There's all this begging for feedback on story sites, so if he leaves an email address, he might expect to get some messages. Sometimes feedback might be a bit worrying, if people start asking for advice or telling about personal problems that do not seem directly connected with the fiction one writes. But most often the mere fact that people take time to write to me they enjoyed what I did is enough to make my day, and I make a point of writing a thank you note, and if their comment goes beyond "Nice work, thanks", to develop a bit on their reaction. Obviously if you start getting lots of feedback, you might have to refrain from engaging into lengthy dialogues. As for giving info on other sites where fiction is available, it's a simple copy and paste, and if you get too many of these questions, you should somehow provide it in your story if the site you post on is OK with it, and why shouldn't they be?
The puzzling thing is that he even got back to you. I've been a bit pissed as a reader when I wrote twenty lines of comment (praise) about a story and that they were not even acknowledged, but then silence is fine with me; it will just save ten minutes the next time this guy posts a story. As Dio points out, there might be some misunderstanding with your message. I think the guy must have had "one of these days" and you should not bother too much.