I worked for one briefly as an intern many years ago. The "CEO" had a self directed and "burn and churn" strategy, working interns as hard as he could till they quit, I saw him make one cry for not working hard enough. He would also split interns into cohorts to prevent communication between the groups, eventually interns wisened up by communicating through linkedin and quit en masse. The owner even got reported to and investigated by the labor bureau although not much came of that. Afterwards I ran into a couple other similar startups while looking for other intern/junior positions and knew to avoid them.
The people who run these companies know to target students/bootcampers. They hangout on beginner forums, discord channels, and college campuses, I remember going to my state university's job fair and probably 80% of the booths there were for some sort of pyramid-scheme/scam.
Ive never seen a software one come close to working, but sadly some people do find success with these shady business models, a good example would be "College Pro Painters". Once they hire you, you are required to pay them thousands of dollars up front for overpriced painting equipment, you are then expected to manage finding clients and painting all on your own. They keep a significant portion of what you earn plus charge all sorts of hidden fees. Most students who join end up painting a few houses before discovering they are only earning like $2/hr and quit, the company is also apparently quite good at scaring students into continuing to work for them by threatening legal action for not paying the "quitting fee"...