I think most people that respond are doing it conversationally, not maliciously. They are asked a question and don't quite understand that they don't have to answer, so they default to saying 'I don't know' out of politeness.
I am guessing they are older, or less inclined to understand the online etiquette of interacting with automated questions and responses.
What might be helpful is if Amazon filtered out the I don't know type of questions as an answer.
c'mon get happy!