Unfortunately the only reasons these "bootcamps" exist is to creater cheaper workforce for tech companies. They don't provide good education, just specialization in the areas that the tech companies decided they want.
However, if companies desire a specific set of skills related to, but not exactly computer science (programming), it makes a lot of sense to create school focused on that particular subject — especially if they're willing to sponsor it. Further, it adds value to society as a whole, as by creating the goods/services people want cheaper, standard of living goes up.
What about the offshore workers? They might benefit for a short time until an even cheaper location opens up, that’s all. Once the jobs are mobile, they will keep moving.
Far better to create indigenous industries.
I've worked with a few bootcamp grads in the past. Some have been absolutely woeful, and others have been some of the most skilled developers I've ever worked with. While the bootcamp itself might be a way to get cheaper workers in, I'd argue that if it's producing good developers then it's a necessary evil.
Also, experience will always be valued by good employers, and an injection of inexperience into the workforce often means rising salaries/rates for senior developers.