Mostly agreed, but as an employee you do have some semblance of material non-public information that gives you a structural edge in assessing the stock. (This probably works better at a 1k-5k company than a Google/FB, but I can't say because I haven't worked at the big faangs).
I've benefited financially from having a good sense of how well things are going and holding/selling accordingly (within the confines of the law and blackout periods, of course).
> non-public information that gives you a structural edge in assessing the stock
This can also cut the other direction too. I had a slightly negative sentiment about Google during my tenure there due to the organization I was in. When earnings call season rolled around it didn't matter since the ads revenue line always dominated everything else.
I've benefited financially from having a good sense of how well things are going and holding/selling accordingly (within the confines of the law and blackout periods, of course).