I dunno why people get so worked up about scout bikers.
First of all, it's a new option for the army, so yay.
Secondly, can you imagine a Space Marine who can't ride a bike? They teach them to pilot a Thunderhawk while still in scouts!
And lastly, you have all sorts of characters riding bikes - I can't possibly imagine they took a class after becoming Chaplains and Librarians, and not during the hypnoinduction in the 10th company.