not clear on your question here.. the asteroid was discovered on June 22'nd.. and reported June 25'th.. that is barely time to confirm its existence and trajectory...
as far as why is it not front page.. it isn't a threat to anyone.. nor a record just an interesting occurrence
Asteroid 2011 MD was discovered Wednesday (June 22) by LINEAR
in the science community it is normal to verify your findings before you report anything on a broad basis... helps to avoid panics