Did any of them commit crimes, civil or war time? Probably, and they should be, or should have been, tried by the appropriate court, and either released or sentenced and transferred to the proper criminal prison to serve their term, or be executed. GITMO is NOT the proper place for them. It is the exact same sort of gulag that the Soviet Union operated during the Cold War for their so-called "enemies of the state". Sadly, most Americans never read Solzhenitsyn.
What's really troubling is the part of the DoJ notice that says, "and such other persons as in the opinion of the Attorney General of the United States are proper subjects for confinement in such institutions." That just shreds the Constitution and burns it to ashes.