You've been reminded of this before, so I suspect you'll ignore it once again and continue on with the untruth of, "...only draft picks in return". What they did was replace a type-A FA with a type-A FA, netting a sandwich pick.
For those upset with the tone of the snippet, it was spot on. Boston, more so than any other team in recent years, did indeed take advantage of this loophole. It doesn't pain me to say that, in fact, they acted in a way that should give you confidence. They saw a way to take advantage of the system and they did. Unfortunately, the replacements they brought had limited production due to injuries.