The sticking point in all this is why it was included in the intelligence briefings to the president, the gang of 8, and I guess now the entire House?
NBC says neither Trump nor Obama were briefed on it*. A summary was included as part of an example of disinformation campaigns included on the "briefing" meeting they had last week. (Which was really a "here's how the process works, here's Dave he'll be the guy you yell at for bad news, here's Steve he's in Bruce Springstein's band he'll be sending you pictures of balls as satellite photos, etc." meeting from what I can tell.)
The "gang of eight" can technically release anything but I thought it had to be joint agreement. That's how the House is getting now apparently because....
Johm McCain got it from the same former MI6 guy the Wall Street Journal DOXXED by sharing his publicly known name publicly and sent it to the FBI (who already had it three months before) because he's an abject moron apparently yet people still refuse to realize he's never been "one of the good ones" or "different" from Trump let alone competent as if his freak out before the debates in 2008 never happened.
The two-page summary was written without the detailed specifics and information about sources and methods included in the memos by the former British intelligence official. That said, the synopsis was considered so sensitive it was not included in the classified report about Russian hacking that was more widely distributed, but rather in an annex only shared at the most senior levels of the government: President Obama, the President-elect, and the eight Congressional leaders.
CNN has also learned that on December 9, Senator John McCain gave a full copy of the memos -- dated from June through December, 2016 -- to FBI Director James Comey. McCain became aware of the memos from a former British diplomat who had been posted in Moscow. But the FBI had already been given a set of the memos compiled up to August 2016, when the former MI6 agent presented them to an FBI official in Rome, according to national security officials.
I think people don't realize the "synopsis was considered so sensitive" here doesn't mean the information was damaging to some broader notion of the country or Trump or whatever but that it was so flimsy that it was damaging to intelligence officials for them to include it in the already vague and poorly sourced report since they knew everyone would latch onto it as we see now.
*Chuck Todd confronted the Buzzfeed guy over this on his show and asked him "what's the difference between what you're doing and so-called fake news?" and the Buzzfeed dude got mad. edit: posted video in politik thread