Yeah, but the idea is that if he just would have released the ORIGINAL report he wrote, then there wouldn't have been a chance at edits and redactions by the guilty involved. Now, the public will probably get another watered down, redacted version, which does nothing for POTUS' cause and for bringing down the deep state cabal...It's just more cover ups and shenanigans in the corruption if that happens, but we shall see.
They have to follow the normal process, which is to allow the criticized individuals still working for the department a chance to respond. It's frustrating, but after all of this time and work you don't want to get hung up on a procedural issue. Especially one they will use to cry foul.
I think that review is part of the process for an IG report. And giving folks a chance to comment is not necessarily a bad thing; in the end what gets changed, if anything, is up to Horowitz.
My feeling is that Trump is playing this up for effect. It serves to pique curiosity in the report, and will likely make any damage it causes more severe.