I can see your point..I don't think they're stupid but i can see problems with them if more that two people with bikes want to ride the bus...The bus capacity is around 50 people in my area...what if all of them want to use the racks that would be impossible.
I really like the idea of having dedicated subway or train cars that would be able to hold many bikes at once and would segregate them from the regular passengers so that they wouldn't annoy people and you could take your bike on the subway or train even during rush hour..
my 2 cents worth..