What is transportism?

Answer 1

Transportism is a socially embedded attitude of prejudice towards users of certain modes of transport. In particular, it is prejudice against all those who do not use motor transport: those who walk, cycle, or use public transport; either out of choice or due to economic situation or disability.

Transportism by the way is not a generally recognized social issue: the word was invented by an Australian radio host under the heading "Greg's Grumbles" and was at least partially aimed at tickling the audience's funny bone.