I don't believe its rude just inquisitive
And I don't feel that way I am usually glad to give people answers or information its fun to explain
I am sure most teachers feel that as well

Then if it is not rude, why do you never answer when people ask you questions?

 

Unless you are farming for a hobby it would be awfully foolish to try to go into business with out at least a Agri Bachelors Degree.

 

Or he watches a lot of DoomsDay Preppers and is thinking about that angle. I believe everyone should grow their own food plants and animals even if its just to learn how.