You might be on to something. Although it’s not too far fetched for someone to get their work done in a few hours and have the rest of the day to themselves. Especially a very competent jr who gets assigned easy work at a slow moving company. I had this experience when I was Jr engineer years ago. I wasn’t given enough work and half the time was just told to spend time learning by manager or Sr Engineer. Heck just browse cscareerquestions and you’ll see several posts about Jr engineers complaining about lack of work and fear of their skills stagnating and not learning enough or fears of being made redundant.

I think you are thinking of Forbes opinion articles, which anyone can submit for. Forbes, like Business Insider, has no paywall and seems to have a low quality threshold. Fortune is still paywalled at over $200 per year after the trial year, while at Forbes an annual subscription is $50 for less ads. If you want to submit an article to Fortune you have to send a pitch to an editor.