Why were the first airplanes "backwards"?
"Backwards" is relative, there are modern aircraft that have forward placed elevator i.e. canard designs that fly quite successfully 



(source)

As for why its not more popular you can read up more on that in why are there no production canard GA aircraft? and Why is the Tu-144 the only commercial airplane with canard configuration? as well as in the answers to lots of 'canard' questions on this site. 

As for why the Wrights did it this way, NASA offers an explanation 


  The placement of the elevators at the front of aircraft is rather
  unique for the Wright flyer. Modern aircraft typically have the
  elevator at the rear, attached to the horizontal stabilizer. The
  Wright's placed their elevator at the front to provide protection to
  the pilot in the event of a crash. (The pilot of this aircraft lies
  next to the engine on the lower wing.) But there is also a static
  performance advantage when the elevator is placed forward. Lifting
  wings have a natural tendency to flip tail over nose because of the
  way the pressure is distributed.


So they were not necessarily backwards so much as different considerations were taken under advisement during the design.