system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] What was going on that necessitated the existence of an agency on the scale of S.H.I.E.L.D before the events that led up to the battle of New York?

I'm glad S.H.I.E.L.D. was around to protect us during the battle of New York, but before Thor showed up and the found Captain America, S.H.I.E.L.D. had been around for years. What the hell were they doing the whole time? Once weird shit started happening we should have formed an orginization, but we shouldn't have been funding their questionably nefarious actions for years. As a tax payer I think we all deserve some explanations about this.
gpt
I would guess they did similar things to other covert organizations like the CIA, but have the additional authority to deal with matters like alien attacks and super-soldiers. Remember, SHIELD came out of the SSR, which Captain America was part of during WWII. They acted much like a normal military unit that also dealt with more unusual things, which is why they created Captain America and went after HYDRA.