Insider trading is not illegal because insiders possess knowledge the rest of the market does not.
Insider trading is illegal because it creates a false perception of unfairness among less sophisticated market participants. (There are other decent reasons too, Matt Levine has written about this extensively too. Yours isn’t one of them)
> Markets as a price discovery mechanism relies upon all participants having access to the same information. Insider trading clearly breaks that fundamental rule.
This only makes sense in a context where all parties have access to equal resources, but that’s not true. A hedge fund paying visa for transaction flow, or flying spy planes above a factory to track production will have more information than other participants.