At my old company (in a small east coast market) the leadership had supported a local boot camp wholeheartedly and highly encouraged teams to bring in junior candidates from each graduating cohort. In the round I participated in we interviewed four candidates for my team. (I was the tech lead.)
Of the four candidates, two were essentially extremely under-prepared on multiple levels. We simply could not even convince ourselves that they had rudimentary coding skills or problem solving intuition. One candidate was marginal but seemed intelligent and possibly able to handle the role.
One candidate was previously working in IT doing helpdesk and project management work and wanted to break into software development. She did quite well on the fizz buzz level coding task and we had a strong belief that she would be able to perform and get up to speed so the company hired her.
She was very intelligent and hard working and she did slowly begin to learn the applications and the tech stack (Java + Spring) but I can't emphasize how much hand-holding, mentoring, and knowledge transfer it required on our part. She was assigned a mentor to do pairing with her and I personally spent a lot of time with her going over the systems and pairing with her. A short time later I moved to another team and then later left the company but my former coworkers report she's doing ok. It worked out but it was definitely a slow and time consuming process.
I think the key challenge is that when a very junior engineer like this gets 12-24 months under their belt they're going to be very attractive to other companies and are very likely to leave. I do not currently believe that the investment that any single company would put in on some of these folks is likely to pay off. The productivity that these folks contribute minus the effort spent on them in 12-24 months is very likely to be a wash unless the person is exceptionally talented.
I get the weird sense that companies recognize that they won't get too much benefit out of mentoring any specific person but that they've collectively decided that they want to increase the number of junior candidates badly enough that they're willing to "take one for the team" in a sense. Perhaps the expectation is that for every junior candidate they train but quickly leaves they'll just get a junior-mid candidate that somebody else trained.
In conclusion, not all candidates from these schools are good and the good ones probably won't stay all that long. It doesn't seem to be an obviously great bargain but companies are clearly willing to take those risks.