I don't know why bicycles should get it but as far as motorcycles yes they do use a lot less fuel than cars, I used to ride motorbikes and up to now I have never known a car that can do 100 miles on half a gallon, that is what I used to get out of a 125cc. Ok bigger bikes may use more but you are still not paying to move all the extra weight of the cars body and lack of streamlining.
can you name the bike you were using? bigger bikes will only do between 40 to 50 mpg which now a days is what most cars will do.
It cost more to run a car than it does to run a bike. It's not rocket science.
so most people would think woz, but it aint believe me, only the other week a few of the lads were comparing bike maintenance to cars and there wasnt a lot in it. only the other day i had a rear tire replaced for 130 quid, which is nothing special and most bike tires will only last around 6,000 miles if they are lucky.