It's not the prosecutors, it's the FBI. The local prosecutors want to charge them, but the big-shot feds come in and say "no evidence here" and get the guys released. From the article:
In the Michigan case, the FBI said Monday that it had no indication that the men had any ties to know terrorist groups. Local prosecutors, however, were standing by the charges.
Good for the prosecutors! The FBI has its head up in a very DARK place. Hope they like it there.
But they could indict a ham sandwich on a hate crime charge for being being "offensive to muslims".....