Unfortunately certain passengers become 'rude' because of the increased
levels of stress and anxiety brought on by the prolonged experiences of
personal inconvenience when traveling from A to B. The big causes of
stress in regard to rail travel are delays, increase in prices and
claustrophobia. Different people have different levels of tolerants
through experiences but if person feels threatened then the common
human reaction is to 'fight' back with fists, words or even a brolly
attack. When that's understood you can hardly blame anyone for the way
they feel or react when placed in such an environment/system and then
increase their stress levels.

To call someone rude is to disregard their perspective, experience and
point of view. (am I being rude too by pointing that out?)