They were going to reveal the Stargate program at the end of S7, but of course, they got renewed and had to keep things going.
At some point, Earth got a secret council, but it still doesn't really make much sense. Like, why would the Chinese let any of this happen?
Then there is also the awkward thing where Sheppard is an Afghan war veteran, which means 9-11 or some other event happened that forced America to go into Afghanistan, so the US was busy fighting their same old terrestrial wars while the entire planet was in danger from alien space bugs.
By Universe, it seems like anyone even related to the Stargate program was allowed to know about it.
