Sorry, but did you think of that maybe they were in the middle of talking to their friends and you were interrupting? It happens all of the time, no matter what the level. I try to answer people if they ask questions, but sometimes I am chatting with three of my friends while sitting in Balefort and it is hard to keep track of conversations, and I don't answer random questions from people I don't know if I am too busy.

It doesn't mean they are being mean or ignoring you, but maybe they are busy chatting with their friends and don't want/like/be able to keep up with interruptions. Not saying you are wrong, some people probably are rude, but a lot of people are just busy looking in the CS or talking to someone else.

Just another way to look at it