[doktrin]

To be fair :

1,000 applicants x 8 minute videos = 133.33 hours, not 8,000

In addition, it's common knowledge that interview questions - whether in person or on youtube - are crafted for the benefit of the interviewer. i.e.

"what's your biggest weakness?" "well, I find it hard to delegate (because I'm such an awesomely hard worker, etc)"

This is inevitable, and not a flaw specific to this format.

However, I think your last point is valid. Realistically, they will be picking people with some background in programming. That said, it's unlikely that applicants to a RoR bootcamp will have absolutely -no- exposure to programming. They might not be professional developers, but I think most of the applicants will have had some exposure to web technology and/or scripting.