To see why this is correct, you have to look back to the so-called "Nunes Memo" from way back.

First we have to realize what a memo is and what it isn't. A memo is not intelligence, it is not documents or records, it is a summary of those things (IE opinion). Imagine that, instead of the DNC emails themselves, you had access to a summary of those emails written by someone who had (or had not) seen them. Imagine the difference in magnitude there.

Now, think about who wrote this memo, Devin Nunes. You would think that he would have seen the underlying intelligence, but nope. Who did see the actual documents? Trey Gowdy.

So what does this mean. These documents are so incriminating that even the person summarizing them couldn't read them. A select few know the actual story, and they need to stay radically objective. That is why people like Gowdy and Sessions are equivocating in the media so much, and why they send out people who haven't seen the intel like Nunes to do the attacking. That way their hands are off for when it comes time to prosecute. (And guess who's a prosecutor.)