During Spartan Ops, the S-IV's mention that Dr. Halsey kidnapped and altered the S-II's and replaced them with clones. If S-IV's know about it and casually mention it in a hanger, surrounded by people, then how is this a secret conspiracy by ONI?

When HtT first aired, I was thrown off because I was under the impression that this was all public information.

Also, does it bother anyone else that Ben says "O-N-I" instead on "Oni"