To get accepted and graduate from a reputable university you have to get good results in standardized tests and work your self through multiple courses for at least 3 years. That by itself doesn't mean anything but there's a level of rigor and self-drive required to succesfully traverse this experience.
I mentored in one of these bootcamp programs and you would be surprised how little people give a shit, even though they are paying. Most of them know that the job placement guarantee is a safeguard for their own laziness.
These programs accept people who think pursing a career in tech would be cool and easy until they realize is a tough learning experience and a tough job. Perhaps tougher than anything else they have done in their lives.
The problem with these companies is that they have to balance the quality of students with the quantity required to meet scale. This is probably the worst type of VC backed business because the investor expectations on scale are in direct conflict with the quality of potential students pre-bootcamp and the demanded quality by employers post-bootcamp.