Ignorance should be treated in proper way. Lets take a hypothetical situation - A kid(X) is given a NEW video game to play, and X doesn't know how to play the game then he/she should be taught the right way to play the game - Learning may come thru' his friends or parent's or someone who takes real interest in him/her or by himself. But kid being curious and impulsive to play, just tries to play the game (without any experience), in those situation the kid may ask a question "How to play this game ? Which Keys for speed?" to another kid(Y) who has mastered the game. Y if he/she is not a good friend to X then the typical reply will be - "You Don't Know This" and Y will never teach the basics too. If X is a strong fella' and has the mental strength and he can master the game with the help of his parent's/friends/by himself then its better for him, but life being tough - probability is in both sides of the coin!! Say if X doesn't have favourable conditions and if this kind of situation repeats the kid is forced to go in to a NUT SHELL!! If this happens in the early stage of life, X might not be aware of (S)he is developing inferiority complex and similarly if Y's behaviour is not checked then it develop in to superiority complex.
Y's kind of response doesn't stop after (S)he turns in to an adult !! If you think deeply why this kind of situation arises - the answer is simple - "Supremacy Over Others" and this thought of supremacy has been sowed in our thinking by our parents/relatives/society!! Its inherent duty of every parent's to teach their sons/daughters to help remove ignorance of others, irrespective of age colour, creed, caste !! If somebody ask help from us, they do so ONLY IF THEY DONT KNOW HOW TO DO IT THEMSELVES, SO INSTEAD OF SAYING "YOU DON'T KNOW THIS SIMPLE THING" PLEASE SHOWER/ENLIGHTEN THEM WITH YOUR KNOWLEDGE / EXPERIENCE !!