Using conspiracy theory as a derogaratory term is a form of doublespeak that shield the conspirators and their conspiracies.
I, for one, will not stop calling conspiracy theories conspiracy theories, regardless whether they are true. Actually, especially when they are true.
Garden-variety corruption doesn't need a conspiracy. The US is today the world leader in high-level, fully legal corruption. It took many decades to get there, but it will take even longer to choke it off, if we ever do.
We even elected an out-and-out con man to the presidency. Russia wishes it could be so corrupt, but just doesn't have the money for it. China does, but its corruption is mostly still technically illegal.
However, you can also form a conspiracy to commit a legal act if it’s got some negative stigma your trying to avoid. For example students may conspire to lower the bar when graded on a bell curve.
Real, mundane conspiracies are numerous, and there are probably some outlandish ones, too. Every proven conspiracy must have started with someone's theory, if not an unprompted admission, so it's not always wrong to theorize. It's just silly to dedicate more than a little brain space*time to theories you've got no evidence for or hope of proving, conspiracy or otherwise.