They certainly do NOT hire everyone they can.

I've worked at a facility for kids with a variety of neurological and psychological issues. Their hiring process was uniquely different. Their interview days were done with groups of applicants, who were given a tour of the facility. That way people could actually see what they were getting themselves into. At the end everyone was offered a job, pending a background check and drug test. It was up to the applicants to say no. They literally did hire everyone they could. They did, because it's impossible to tell in advance who would last more than 2 weeks working with those kids.

Again your imagination fails. You can't even conceive what it might actually be like when a company actually hires everyone they can.