I don't think they can comment. The FBI works for the DOJ. I believe the DOJ's directive is not to comment especially within three months of an election. Comey thought he was God and did what he wanted. The FBI is not suppose to tell the public the results of their investigations. That's up to the DOJ. Comey's ego told him he was in charge, not the Attorney General.
Again, as I said before, they can comment, but usually don't, because that wouldn't be following policy. Comey commented on the Hillary thing, so that proves they can can and did comment. What is so hard to understand? It's the English language after all.
And Barr has commented on a couple on ongoing investigations against Trump's adversaries, so that also proves they they can comment too. How would we know about the Dunham investigation and all the rest, if they can't comment on it.
There is a policy around my house that everyone leaves their muddy shoes outside the door. But I can, and have, walked around the house in muddy shoes. My wife yells at me for not following policy, but sometimes I forget to follow policy, as evidenced by my wife yelling at me and the mud all over the floor. Just because it is policy, does mean you can't do it anyway. I learned the hard way.
The next time your wife tells you you can't do something, go ahead and do it anyway, so you understand you can do it after all. Maybe go buy a gun or something.
What is baffling is that you keep saying they can't comment, and yet you even admitted they can comment a couple of posts ago.
That's tortured logic. Of course they can if they want too. They just don't want too.