This is absolutely incorrect. Whole industries exist to generate information advantages for trading. It’s perfect legal and encouraged for price discovery and market efficiency reasons.
It becomes illegal when I have an obligation to the other counterparties in the trade.
Of course one party in the trade may actually have more information than the other. But the point is that they are both trading on the basis of public information. The industries you mention are involved in harvesting and analysing that public information, not selling inside information.
> It becomes illegal when I have an obligation to the other counterparties in the trade.
Again, I think you have it backwards: you have an obligation to the other counterparties (not to trade on inside information) because we have decided that insider trading should be illegal.
It might be expensive to do so, but they could do it.
Insider trading is slightly unique is that an outsider could not generate the same information as would be available to an insider. Their unique position is that the organisation they are part of is `inventing` information 'from thin air' (so to speak) on the basis of the decisions they are making.