Ask HN: should you bug or spam users who don't end up using your app?

I signed up for an app just to check out their tool and interface. I didn't really get what their app does initially. After checking out, I realize that I have no use for it, but the founder sent me two emails straight asking for feedback.

Do you do that? Isn't that kind of spam? What's your thoughts? Isn't no-reply an answer on its own?