I said this in the comments section of the first article: part of the rational behind the J-1 program is to help spread pro-American sentiment overseas, which I personally believe has a value. With regards to taking jobs that should be filled by Americans, there's perhaps some level of unfairness in certain industries like that of fish processing which, as "in a small town" points out, has bread a form of indentured servitude over the years. That's been the case even before the J-1 program started.