Correct, but they can access the information as soon as it is revealed.
Consider the case where a company knows that the drug they are selling is dangerous but keeps it a secret. Insiders know of the dangers and so bet against the company in the market (obviously this is illegal right now). The insiders make a profit in the short term, and investors also in the short term lose out (which they were going to do anyway, the losses come sooner), but in the long term the secret information is revealed to the benefit of everybody.
I don't see how this is responsive to what I wrote. Are you arguing that insider trading is no big deal? If so, what you're actually saying is "insider trading is no big deal because eventually bad information does reach the public."
But I never said insider trading was bad because it caused people to keep information a secret. You're responding to an argument I didn't make.
Consider the case where a company knows that the drug they are selling is dangerous but keeps it a secret. Insiders know of the dangers and so bet against the company in the market (obviously this is illegal right now). The insiders make a profit in the short term, and investors also in the short term lose out (which they were going to do anyway, the losses come sooner), but in the long term the secret information is revealed to the benefit of everybody.