Well I say hi to everyone and if they don't want to wave or say hi back "I just ignore it". It's rude, but hey sometimes people don't hear with wind blowing in their ears or they have their gaze fixed, concentrating and don't see you wave. Who knows.
I think my bike is a road bike with straight bars so if people snub me oh well, "their loss" as far as I am concerned.

Around here though, I don't run into many other riders, but when I do they have been generally friendly back. Maybe not over enthusiasticly so, but friendly none the less.
I'm not a racer or a rider that gets so fixated on my riding that I don't notice others, I am out there to have fun riding my bike and get in shape and hopefully lose some weight. I can understand though others that are training and not wanting their concentration interrupted.
Then there is just the fact that people now a days "a lot of them but not all" are just rude!! I don't like to generalize although I have been known to get frustrated and do it. LOL
Ecspecially with the man thing.