Although here is a possible explanation for all this:
It's an endless time loop. Meaning: Some time in our Earth's future, we'll establish a colony on another world, but (possibly unknown to them) our fleet will be swept back in time before it can set up the colony.
That colony will be Kobol.
So the reason these colonials are a copy of our civilization is because they're descended from us, not ancestors OF us.
Well if that idea were true, then remember...
the cylons and the BSG population came to our earth and procreated with the indigenous humans...and if that's part of the loop, then which came first? The chicken or the egg? 
