Because even if FreeShop didn't have its custom cache for game data, the title key database does not accept encrypted title keys, since they can't be tested/confirmed working. The site accepts a decrypted title key, tests that it's legit, then the owner has to manually encrypt it and add the encrypted key himself. This takes time, but means every key on there is 100% guaranteed to be correct.
In regards to the site having games early because of broken street dates, that isn't true, carts don't have title keys, only eShop purchases. Early release of a game at a shop won't help with title keys at all.